908 + Interview Questions in Chemistry in Class 7

1.	Among the following types of chemical reactions , application of metal reactivity series is involved with which reaction?
Answer» chemical combination of`O_(2)and H_(2)O`. Chemical DISPLACEMENT Chemicaldecomposition Double decomposition. Solution :In displacement REACTIONS , APPLICATION of metal REACTIVITY series is involved.

Discussion

2.	Among the following strong acid is
Answer» PHOSPHORIC ACID carbonic acid SULPHURIC acid acetic acid Solution :Sulphuric acid is a STRONG acid.

Discussion

3.	Among the following reactions , identify the synthesis reaction.
Answer» `2SO_(2)+O_(2)to2SO_(3)` `C+O_(2)toCO_(2)` `CaO+H_(2)OtoCa(OH)_(2)` `2H_(2)Oto2H_(2)+O_(2)` SOLUTION :`C+O_(2)toCO_(2)` is an EXAMPLE of synthesis REACTION.

Discussion

4.	Among the following, identify an extremely corrosive alkali.
Answer» Ammonium HYDROXIDE Calcium hydroxide POTASSIUM hydroxide Magnesium hydroxide Solution :Potassium hydroxide is EXTREMELY corrosive ALKALI

Discussion

5.	Among the following, a pair of compound and an element respectively is
Answer» IRON powder, rust powder. rust powder, iron powder. lime, rust powder. rust powder, lime. Solution :Hydrated FERRIC oxide is rust which is a COMPOUND. Iron powder is an ELEMENT.

Discussion

6.	Among the following a pair of a compound and an element respectively is
Answer» IRON POWDER, RUST powder. rust powder, iron powder. lime, rust powder. rust powder, lime. Solution :Rust is COMPOUND that is hydrated FERRIC oxide. Iron powder is an element.

Discussion

7.	Ammonium hydroxide is an _______ (acid/ alkali)
Answer» SOLUTION :AMMONIUM HYDROXIDE is an ALKALI.

Discussion

8.	Ammonium hydroxide is an alkali.
Answer» SOLUTION :As `NH_(4)OH` is soluble in water it is alkali

Discussion

9.	Ammonium chloride is a sublimable substance.
Answer» Solution :TRUE AMMONIUM chloride undergose SUBLIMATION and it is a sublimable SUBSTANCE.

Discussion

10.	"All pure substances are homogenous in nature" Justify.
Answer» Solution :All PURE substances sontain particle of only ONE KIND having definite set PROPERTIES and their composition cannot be altered by any physical means so we can say that all pure substances are homogenous in nature.

Discussion

11.	Air is a homogeneous mixture of gases which also contains argon and nitrogen which are used for filling electric bulbs. But air is not filled in eletric bulbs. But air is not filled in electric bulbs because
Answer» the active component of air oxidizes the filament the boiling point of air is greater then that of ARGON or nitrogen air has impurities LIKE dust particles air exerts more pressure Solution :SINCE air consists of an active component that is OXYGEN, it electric bulbs are fills are with inert GAS like argon or chemically inert nitrogen.

Discussion

12.	Air is a homegeneous mixture of gases which also contains argon and nitrogen which are used for filling electric bulbs. But air is not filled in electric bulbs because
Answer» the active component of air oxidizes the filament the BOILING point of air is greater than that of argon or nitrogen air has impurities like dust particles Solution :SINCE air CONSISTS of an active component that is oxygen, it oxidises tungsten filment or any other METAL used as a filment. Hence ELECTRIC bulbs are filled with inert gas like argon or chemially inert nitrogen.

Discussion

13.	Aeroplanes usually fly in the zone of mesophere.
Answer» SOLUTION :AEROPLANES USUALLY fly in the zone of STRATOSPHERE.

Discussion

14.	Aeroplanes usually fly in the stratosphere because
Answer» of the presence of ozone layer. of the atmosphere being turbulent. of the DECREASE in temperature with altitude. of the ABSENCE of CONVECTION current. Solution :AEROPLANES fly in the stratosphere DUE to the absence of convection current. Because the temperature gradually increases with increases with increase in altitude due to the absorption of highly energetic UV radiations. Since there is no turbulence in the atmosphere of the stratosphere, aeroplanes usually fly in the stratosphere.

Discussion

15.	Addition of ______ releases ______ which helps in killing the harmful bacteria present in water.
Answer» SOLUTION :Addition of BLEACHING POWDER releases CHLORINE which helps in KILLING the harmful bacteria present in water.

Discussion

16.	Addition of acid to water, ______ the conductivity.
Answer» Solution :ADDITION of ACID to water increases the CONDUCTIVITY.

Discussion

17.	Acids turns methyl orange solution _________.
Answer» Solution :ACIDS turn methyl ORANGE solution PINK.

Discussion

18.	Acids turn methyl orange solution pink.
Answer» SOLUTION :ACIDS TURN methyl orange solution PINK.

Discussion

19.	Acidic and double salts among the following are respectively
Answer» POTASH alum and sodium phosphate sodium dihydrogen phosphate and mohr's SALT mohr's salt and CALCIUM hydroxy chloride. sodium phosphate and mohr's salt Solution :ACIDIC salt is sodium dihydrogen phosphate. Double salt is Mohr's salt.

Discussion

20.	Acid formed as a result of lightening reaches the earth's surface through precipitation, thus contributing to the acid rain as well to the growth of plants. Justify.
Answer» Solution :During ACID rain, the nitric acid formed as a RESULT of lightening process in very DILUTE form is washed down to earth and reacts with metal CARBONATES to form nitrates. `CaCO_(3)+2HNO_(3)toCa(NO_(3))_(2)+CO_(2)+H_(2)O`. Nitrates so farmed, act as excellent NURTIENTS for the growth of plants.

Discussion

21.	(a) What is pollution ? (b) Write a short note on (i) ozone depletion and (ii) hazards of carbon monoxide
Answer» Solution :(a) Air pollution: The atmopheric composition of gases change to the addition of other gases and suspended particles into atmosphere mainly by human induced activies. This build up of other gases and suspended particulate matter is toxic to organisms living on the earth's surface. The variation in the composition of atmopheric air due to the relese of harmful gases is called air pollution. (b) (i) Ozone DEPLETION : Ozone presetn in troposphere CONTRIBUTES GREEN house effect. Ozone present in stratosphere plays a vital role inn protecting the life on earth's surface from harmful UV raditions. Ozone layer acts as a shield as it absorbs highly energetic harmful UV radiations. Pollutants such as `CFC_(s)` when reach stratophere reach stratophere react with ozone and thus depletes the ozone layer in a period of time. UV radiations reach tropospheric layer due to the holes created in ozone and affect plant and animal life. Prevention : Discovery of alternative substance for `CFC_(s)` used in refrigeration (ii) Hazards caused by carbon monoxide: As the percentage of CO increases in atmophere, it affects the respiratory system. CO has 200 times mover affinity for haemoglobin over oxygen and forms a stable compound called carboxy haemoglobin which causes suffocation and some times it is even fatal to human life. Prevention: Reduction in the burning of fossil fuels, cigarettes etc. As the pollutants increase in atmospheric air it affects plant and animal life, causes respiratory problems, damge to monuments. PARTICULARLY, the lead particles from smoke of motor engines cause damage to the nervous system.

Discussion

22.	A teacher showed demonstration of action of acids on the metals in the laboratory. After the activity was over, one naughty student took an alluminium rod. He dipped it in a bottle containing concentrated nitric acid. Later, he dipped it in a beaker containing dilute H_(2)SO_(4) But, he did not find any bubbles coming out. He was surprised because he was able to see bubbles coming out when a metal rod is dipped in sulphuric acid when teacher did the experiment. He then approached the teacher and asked what is wrong with his activity. Predict the answer given by the teacher.
Answer» Solution :`HNO_(3)` is HIGHLY corrosive in nature. As a result it forms an oxide layer on A1 rod which acts as a passive layer. This passive layer prevents the reaction between A1 and `H_(2)SO_(4)`. And hence no LIBERATION of HYDROGEN gas.

Discussion

23.	A substance which is formed by the chemical combination of two or more elements is called a _______ .
Answer» SOLUTION :compound A compound is a pure substance FORMED from TWO or more elements COMBINED chemically in a definite proportion by weight.

Discussion

24.	A student has a mixture consisting of charcoal and sulphur powder. He adds a certain reagent where he observes that one of the component goes into the solution state. Name the techniques by which the components can be separated.
Answer» Solution :The REAGENT is carbon disulphide which DISSOLVES sulphur. CHARCOAL can be separated by FILTRATION. Sulphur from the solution can be separated by evaporation.

Discussion

25.	A stable neutral atom 'X' contains two completely filled orbits . Findout its mass number if it consists of 10 neutrons.
Answer» Solution :Electrinic configuration X is 2 , 8 A-Z= NUMBER of neutrons A- 10 = 10 `:.`MASS number (A)is=20

Discussion

26.	A sample of hard water is taken in two containers A and B. To container 'A ', a detergentis added and soap is added to container 'B'. The water in 'A' is moreefficient in cleaning than the water in 'B' . Justify.
Answer» Solution :Effectiveness of SOAP is reduced when used in hard water. Hardness in water is caused by the presence of mineral salts mostly of CA and Mg. The mineral salt REACTS with soap to form an insoluble precipitate known as scum. Lather formation is reduced. Detergent forms solublecompounds withcalcium andmagnesium and hence does not form scum with hard water. Due to this reason, water in 'A' is more efficient in CLEANING than water in 'B'.

Discussion

27.	A salt 'X' of a metal which is used in the galvanizing process on heating produces an oxide of that metal 'Y' and a gas 'Z' . Z is used in the preparation of soda water, and 'Y' is used as a base of white paint. Identify X, Y, Z.
Answer» SOLUTION :Since 'Z' is used in MAKING soda water, it is carbon DIOXIDE. Themetalcarbonate is zinc carbonate because zinc carbonate onheating produces zinc oxide and carbon dioxide. Zinc oxide is used as a PAINT. So 'X' is zinc carbonate, 'Y' is zinc oxide and 'Z' is carbon dioxide.

Discussion

28.	A salt 'X' has a positive radical in which the metal has electronic configuration 2, 8, 8, 2. The negative radical is formed from acid used in soft drinks. One molecule of the salt 'x' reacts with one molecule of base. Predict the formula of the salt 'x'.
Answer» `Mg(HCO_(3))_(2)` `Ca(HCO_(3))_(2)` `CaCO_(3)` `MgCO_(3)` Solution : The acid used in soft drinks is `H_(2)CO_(3)`. The metallic radical in SALT should be `Ca^(+2)`. The formula of the acidic salt should be `Ca(HCO_(3))_(2)`.

Discussion

29.	A salt 'A' on heating forms the oxide of the metal 'B' and a gas 'C'. 'B' is used in white washing . WhenC is passed through water it forms 'D'. Identify A, B, C and D. Justify the usage of 'C' for the above purpose.
Answer» Solution :Metal carbonate is calcium carbonate which on heating forms calcium oxide and carbon dioixde. Calcium oxide is ADDED to water to form calcium hydroxide which is used for white washing. Carbon dioxide forms CARBONIC acid (a week acid ) when DISSOLVED in water and turns lime water MILKY when passed through it. So 'A' is calcium carbonate, B is calcium oxide, 'C' is carbon dioxide and D is carbonic acid. When whitewashing of walls is done, calcium hydroxide reacts with atmospheric `CO_(2)` to form a white powdery coating of calcium carbonate.

Discussion

30.	A reddish brown coloured metal 'P'and silvery white coloured metal Q both are highly ductile andare good conductors of heat and electricity. P plays a major role in the preparation of brass and bronze whereas Q is the most abundant element in theearth's crust, after oxygenandsilicon, but Q is used as a substitute for P. Give reasons.
Answer» Solution :Brass and bronze mainly contain contain copper which is a reddish brown COLOURED metal. The most abundant element in the earth's crust after oxygen and silicon is ALUMINUM whichis SILVERY white coloured metal. So 'P' is copper and 'Q' is alminium. Both copper and aluminium are GOOD conductors of heat and electricity. Since copperis costly metal, aluminium is USED as a substitute for copper.

Discussion

31.	A pure substance is __________ in nature .
Answer» SOLUTION :HOMOGENEOUS A PURE SUBSTANCE is homogeneous in NATURE

Discussion

32.	A pure substance is homogeneous in nature.
Answer» Solution :TRUE Pure SUBSTANCE are made up of identical molecules and hence are HOMOGENEOUS in NATURE.

Discussion

33.	A nonmetallic element is converted into a compound 'X' after a series of reactions. A little amount of 'X' when tested with blue litmus turns to red. 'X' on complete reaction with another compound 'Y' gave the product which did not respond to litmus test. Identify the correct sequence of the reactions. (a) 2SO_(2) + O_(2) rarr 2SO_(3) (b) H_(2)SO_(4) + 2KOH rarr K_(2)SO_(4) + 2H_(2)O (c) SO_(3) + H_(2)O rarr H_(2)SO_(4) (d) S + O_(2) rarr SO_(2)
Answer» acdb dacb bcad dcba Solution :(i) `S + O_(2) rarr SO_(2)` (ii) `2SO_(2) + O_(2) rarr 2SO_(3)` (iii) `SO_(3) + H_(2)SO_(4)` (IV) `H_(2)SO_(4) + 2KOH rarr K_(2)SO_(4) + 2H_(2)O`

Discussion

34.	A non-metallic element X is a good conductor of electricity in one form and is a bad conductor of electricity in another form. Comment on thethermal conductivity of both forms. Identify theelement and mention the above two forms ofX.
Answer» Solution :Carbon OCCURS as graphite and diamond in free state. Graphite is a good conductor of electricity and diamond is a bad conductor of electricity . So the element 'X' is carbon and the TWO forms of X are graphite and diamond. Diamond is a good thermal conductor whereas graphite it a poor thermal conductor.

Discussion

35.	A non-metal "X" with electronic configuration 2, 8, 6 forms corresponding-ous and-ic acids. Identify both the acids and explain the method of dilution of corresponding-ic acid.
Answer» Solution :Non-metal with electronic configuration 2, 8, 6 is sulphur. Corresponding ous and ic acids of sulphur are `H_(2)SO_(3) "and" H_(2)SO_(4)` respectively. `H_(2)SO_(4)` is diluted by adding acid to water with CONTINOUS stirring because addition of water to acid is associated with LIBERATION of large amount of heat at a time which may lead to violent and EXPLOSIVE REACTION.

Discussion

36.	A non-metal 'X' is lustrous, insoluble in water but soluble in alcohol, when it reacts with another metallic element 'Y' , it forms a substance'Z' which are used in cloud seeding or artificial rain. Identify X, Y and Z. What are theadvantages of artificial rain? Is there anysubstances other than Z than Z that can be used for artificial rain? If so,what are they?
Answer» Solution :A lustrous non-metal which is soluble inalcohol is iodine. It REACTS with the metallic element silver to form silver iodide which is used in cloud seeding or artificial rain. So 'X' is iodine, 'Y' is iodine, 'Y' is silver, Z is silver iodide. Artificial rain is very MUCH useful inagriculture at the time of DROUGHT or WATER scarcity. Silver nitrate and dry ice (solid carbon dioxide) can also be used for artificial rain.

Discussion

37.	A negative ion of an atom element Xhas18 electrons and 16 protons . Calculatethe number of electrons and protons in its corresponding atom . Also calculate the number of nuetrons , if the mass number is units than double the number of protons.
Answer» Solution :16 protons MEANS that the atomic number of the element (X) is 16 . Thatis the ELECTRONIC configuration is , 2 , 8 , 6. It has to gain twoelectrons to attain octet configuration . Hence , the dinegative ion possesses 18 ELECTRONS. `(X^(-2))=16+2=18`. Mass number = 2+ 2 (number of protons) = 2 + 2 (16) = 34 `:.:.`Number of NEUTRONS = 18

Discussion

38.	A mixture of two solids is generally ________ while a mixture of any number of gases _______ .
Answer» SOLUTION :heterogeneous, HOMOGENEOUS A mixture of two SOLIDS is generally heterogeneous while mixture of any NUMBER of gases is homogeneous.

Discussion

39.	A mixture of chalk powder and ammonium chloride can be separated by
Answer» distillation evaporation filtration SUBLIMATION Solution :Since ammonium chloride is a sublimable SUBSTANCE, it can be separated from CHALK powder by sublimation

Discussion

40.	A mixture of alcohol and water is an example of _________ mixture .
Answer» SOLUTION :homogeneous ALCOHOL is uniformly DISTRIBUTED in water and hence it is an EXAMPLE of a homogeneous mixture.

Discussion

41.	A mixture contains three components namely glucone-D, water and sand. These three can be collected separately by
Answer» filtration and evaporation filtration and sublimation. filtration and distillation. sedimentation and decantation. Solution :SAND is insoluble in water , it can be SEPARATED by filtration. Gluocone-D is SOLUBLE in water , can be seprated by distillation and water is COLLECTED separately.

Discussion

42.	A mixture contains three components namely camphor powder, common salt and water. These can be separated by
Answer» FILTRATION and distillation filtration, SEDIMENTATION and decantation. sublimation and distillation. sublimation, sedimentation and decantation. Solution :since CAMPHOR is insoluble in water it can be SEPARATED by filtration. Common salt from water can be separated by distillation.

Discussion

43.	A metallic element is converted into a compound 'A' after a series of reactions. Compound 'A' turns red litmus blue. 'A' on reaction with another compound B which turns blue litmus red gave a compound 'C' which responded to litmus test like compound 'B'. 'C' on further reaction with 'A' gave a compound 'D' Which did not respond to litmus test. Identify the correct sequence of steps for the formation of A, B, C and D. (a) NaOH + H_(2)SO_(4) rarr NaHSO_(4) + H_(2)O (b)4Na + O_(2) rarr 2Na_(2)O (c) NaHSO_(4) + NaOH rarr Na_(2)SO_(4) + H_(2)O ltBrgt (d) Na_(2)O + H_(2)O rarr 2NaOH
Answer» acbd bcad bdac dbac Solution :(i) `4NA + O_(2) rarr 2Na_(2)O` (II) `Na_(2)O + H_(2)O rarr 2NaOH` (III) `NaOH + H_(2)SO_(4) rarr NaHSO_(4) + H_(2)O` ltBrgt (iv) `NaHSO_(4) + NaOH rarr Na_(2)SO_(4) + H_(2)O`

Discussion

44.	Ametal M shows variable valencies 2 and3. Calculate the ratio of oxygen atom present in their corresponding sulphates.
Answer» `1:3` `3:1` `3:4` `3:2` Solution :LET the METAL be X . The compounds possible are `XSO_(4)and X_(2)(SO_(4))_(3)`.The NUMBER of oxygen atomspresentare 4 and 12 respectively . Ratio of oxygen ATOMS are`4 : 12=1:3`

Discussion

45.	A metal (M)and a non - metal (X) form a compound withformula M_(4)X_(3). Predict the electronic arrangements of M and X assuming that M has three occupied shells and X has two occupied shells. Also derive the formulae of (a)sulphate (b)dihydrogen phosphate ( c) hydroxide of ion of M.
Answer» SOLUTION :Formula`M_(4)X_(3)`corresponds to`M^(+3)X^(-4)`.M has THREE occupied SHELLS K, Land M . Thenumber of electrons in valece shell is equal to 3. theelectronic arrangement could be 2 , 8 , 3 which corresponds to Z = 13 that is aluminium . X has two occupied shells K and L and L shell must have 4 electrons . theelectronic arrangement could be 2 , 4which corresponds to Z = 6 thatis carbon. (a)`{:(Al^(+3)SO_(4)^(-2),),(Al_(2)(SO_(4))_(3),):}` (b)`{:(Al^(+3)H_(2)PO_(4)^(-),),(Al(H_(2)PO_(4))_(3),):}` (c )`{:( Al^(+3)OH^(-),),(Al(OH)_(3),):}`

Discussion

46.	A metal carbonte 'X' when treated with dil HCIgeives Y.Y when used in mines area reduces suspended particulate matter in atmosphere. Identify Y.
Answer» NaCI `H_(2)CO_(3)` `CaCI_(2)` `CO_(2)` Solution :Anhydrous calcium CHLORIDE is deliquescent in nature which ABSORBS moisture and forms a solution.Thus `CaCI_(2)` solutionformed doesn'tallow the dust particles and other SUSPENDED particulate matter to RISE. `underset((X))(CaCO_(3))+HCItounderset((Y))(CaCI_(2))+CO_(2)+H_(2)O`

Discussion

47.	(a) Mention the causes for water pollution. (b) Mention different types of pollution. (c ) Mention the control measures for water pollution.
Answer» Solution :(a) Defecation of living beings, industrial operation, agricultural activities, thermal pollution and atomic reactors are the different causes of water pollution. (b) Microorganisms, POISONOUS METALLIC salts, residual AMOUNT of artificial fertilizers, pesticides, insecides and hot water are different types of pollutant. (c ) Usage of pit latrines, conversion of cow dung into biogas and the left over slurry can be used as manure. Removal of metallic salts by chemical treatment of water before discharging it, usage of natural manure in place of artificial fertilizers, usage of natural pesticides, avoiding SPRAYING of chemicals in rainy season, usage of drip irrigation, cooling and RECYCLING of water in the industry, and cooling by cooling towers before discharching it into water bodies are some of the control measures of water pollution.

Discussion

48.	A list of four differenct substaces is given below. The methods of preparation of the substances are also given. Arrange the methods of preparation in the order of the sbstances given. (i) O_(2) (ii) CO_(2) (iii) SO_(2) (iv) P_(2)O_(5) (a) Burning of non-metal produces dense white fumes. (b) Burning of non-metal with sparkles and crackling sound. ( c) Heating of onw of the binary compound of hydrogen. (d) Burning of non-metal with brilliant blue flame.
Answer» cbda bcdea adcb cdab Solution :(i) OXYGEN in is prepared by heating of hydrogen peroxide. (II) Carbon burns with SPARKLES and carcking sound to give `CO_(2)`. (iii) Sulphur burns with BRILLIANT blue flame to give `SO_(2)`. (iv) `P_(2)O_(2)` appears as dense WHITE fumes when phosphorus is burnt with oxygen.

Discussion

49.	A homogeneous mixture among the following is
Answer» milk MUDDY water smoke air Solution :Air is a HOMOGENEOUS mixture of DIFFERENT GASES

Discussion

50.	(a)H_(2)+Br_(2)to2HBr(b)HBr+NaOHtoNaBr+H_(2)O(c )2NaBr+Cl_(2) to2NaCl+Br_(2)(d)2NaCl to2Na+Cl_(2)Arrange the above reactions in order s double displacement reaction, combination reaction, decomposition reaction and displacement reaction.
Answer» badc<BR>bdac bacd abdc Solution :(i) `HBr+NaOHtoNaBr+H_(2)O` (II)`H_(2)+Br_(2)to2HBr` (iii)`2NaCl to2Na+Cl_(2)` (IV)`2NaBr+Cl_(2)to2NaCl+Br_(2)`

Discussion

Explore topic-wise InterviewSolutions in Current Affairs.

Among the following types of chemical reactions , application of metal reactivity series is involved with which reaction?

Among the following strong acid is

Among the following reactions , identify the synthesis reaction.

Among the following, identify an extremely corrosive alkali.

Among the following, a pair of compound and an element respectively is

Among the following a pair of a compound and an element respectively is

Ammonium hydroxide is an _______ (acid/ alkali)

Ammonium hydroxide is an alkali.

Ammonium chloride is a sublimable substance.

"All pure substances are homogenous in nature" Justify.

Air is a homogeneous mixture of gases which also contains argon and nitrogen which are used for filling electric bulbs. But air is not filled in eletric bulbs. But air is not filled in electric bulbs because

Air is a homegeneous mixture of gases which also contains argon and nitrogen which are used for filling electric bulbs. But air is not filled in electric bulbs because

Aeroplanes usually fly in the zone of mesophere.

Aeroplanes usually fly in the stratosphere because

Addition of ______ releases ______ which helps in killing the harmful bacteria present in water.

Addition of acid to water, ______ the conductivity.

Acids turns methyl orange solution _________.

Acids turn methyl orange solution pink.

Acidic and double salts among the following are respectively

Acid formed as a result of lightening reaches the earth's surface through precipitation, thus contributing to the acid rain as well to the growth of plants. Justify.

(a) What is pollution ? (b) Write a short note on (i) ozone depletion and (ii) hazards of carbon monoxide

A substance which is formed by the chemical combination of two or more elements is called a _______ .

A student has a mixture consisting of charcoal and sulphur powder. He adds a certain reagent where he observes that one of the component goes into the solution state. Name the techniques by which the components can be separated.

A stable neutral atom 'X' contains two completely filled orbits . Findout its mass number if it consists of 10 neutrons.

A sample of hard water is taken in two containers A and B. To container 'A ', a detergentis added and soap is added to container 'B'. The water in 'A' is moreefficient in cleaning than the water in 'B' . Justify.

A salt 'X' of a metal which is used in the galvanizing process on heating produces an oxide of that metal 'Y' and a gas 'Z' . Z is used in the preparation of soda water, and 'Y' is used as a base of white paint. Identify X, Y, Z.

A salt 'X' has a positive radical in which the metal has electronic configuration 2, 8, 8, 2. The negative radical is formed from acid used in soft drinks. One molecule of the salt 'x' reacts with one molecule of base. Predict the formula of the salt 'x'.

A salt 'A' on heating forms the oxide of the metal 'B' and a gas 'C'. 'B' is used in white washing . WhenC is passed through water it forms 'D'. Identify A, B, C and D. Justify the usage of 'C' for the above purpose.

A pure substance is __________ in nature .

A pure substance is homogeneous in nature.

A non-metallic element X is a good conductor of electricity in one form and is a bad conductor of electricity in another form. Comment on thethermal conductivity of both forms. Identify theelement and mention the above two forms ofX.

A non-metal "X" with electronic configuration 2, 8, 6 forms corresponding-ous and-ic acids. Identify both the acids and explain the method of dilution of corresponding-ic acid.

A negative ion of an atom element Xhas18 electrons and 16 protons . Calculatethe number of electrons and protons in its corresponding atom . Also calculate the number of nuetrons , if the mass number is units than double the number of protons.

A mixture of two solids is generally ________ while a mixture of any number of gases _______ .

A mixture of chalk powder and ammonium chloride can be separated by

A mixture of alcohol and water is an example of _________ mixture .

A mixture contains three components namely glucone-D, water and sand. These three can be collected separately by

A mixture contains three components namely camphor powder, common salt and water. These can be separated by

Ametal M shows variable valencies 2 and3. Calculate the ratio of oxygen atom present in their corresponding sulphates.

A metal (M)and a non - metal (X) form a compound withformula M_(4)X_(3). Predict the electronic arrangements of M and X assuming that M has three occupied shells and X has two occupied shells. Also derive the formulae of (a)sulphate (b)dihydrogen phosphate ( c) hydroxide of ion of M.

A metal carbonte 'X' when treated with dil HCIgeives Y.Y when used in mines area reduces suspended particulate matter in atmosphere. Identify Y.

(a) Mention the causes for water pollution. (b) Mention different types of pollution. (c ) Mention the control measures for water pollution.

A homogeneous mixture among the following is

(a)H_(2)+Br_(2)to2HBr(b)HBr+NaOHtoNaBr+H_(2)O(c )2NaBr+Cl_(2) to2NaCl+Br_(2)(d)2NaCl to2Na+Cl_(2)Arrange the above reactions in order s double displacement reaction, combination reaction, decomposition reaction and displacement reaction.

Addition of releases which helps in killing the harmful bacteria present in water.

A mixture of two solids is generally __ while a mixture of any number of gases _ .