908 + Interview Questions in Chemistry in Class 7

1.	Themetals with the least tensile strength is
Answer» iron aluminium ZINC copper Solution :Zinc is non-malleable and non-ductile HENCE it has the LEAST TENSILE STRENGTH.

Discussion

2.	The metallic compounds of which among the following metals is involved is involved in cloud seeding ?
Answer» Mercury Aluminium Copper Silver Solution :Silver nitrite or silver IODIDE is used in CLOUD seeding for artificial RAIN.

Discussion

3.	The maximum number of electrons that can be accommodated in the outermost orbit is equal to _______.
Answer» Solution :8 Eight is the maximum number of electrons that can be ACCOMMODATED in the VALENCE shell.

Discussion

4.	The maximum number of electrons that can be accommodated in an orbit is equal to __________ where n is the number of orbits.
Answer» `4n^(2)` `2n^(2)` `(2n+1)^(2)` `n^(2)+4` Solution :The maximum number of electrons that can be accommodated in an ORBIT is EQUAL to 2N2.

Discussion

5.	The maximum number of electrons in L shell is two.
Answer» SOLUTION :False The maximum number of ELECTRONS in L shell is eight.

Discussion

6.	The mass of an electron is _______ times that of mass of a proton.
Answer» Solution :`(1)/(1837)` The MASS of ELECTRONS is `(1)/(1837)` TIMES that of mass of a PROTON.

Discussion

7.	The major component of naturalgas is _________
Answer» Solution :METHANE The major COMPONENT of natural gas is methane

Discussion

8.	The inter conversion involved in usage of "odonil" in wash room is ________ .
Answer» sublimation DEPOSITION MELTING freezing Solution :Odonil undergose sublimation, that is, solid is converted into VAPOUR state.

Discussion

9.	The increase in the proportion of ………… in air leads to global warming.
Answer» CO `CO_(2)` `SO_(2)` `N_(2)` Solution :The increase in the proportion of CO2 in air LEADS to global WARMING.

Discussion

10.	The holes in the ozonosphere is due to the attack of a pollutant that is released from
Answer» automobiles AIR CONDITIONERS industries volcanic eruptions Solution :Holes are created in the ozone LAYER due to the ATTACK of CFC'swhich are released from refrigerators and air conditioners.

Discussion

11.	The formulae ofa compound when a positiveradical with valency 2 and nedical with valency 1 combine is _______.
Answer» `B_(2)A` `A_(2)B` `AB_(2)` AB Solution :

Discussion

12.	The conversion of a liquid to its solid state on cooling is called __________ .
Answer» SOLUTION :solidification The process involving the CHANGE of from liquid to SOLID on cooling is called solidification.

Discussion

13.	The compounds X and Y combine to form a compound Z. 'Z' which is need for construction of monuments gets affected by acid rain. The compound X is used in white washing. Identify X, Y and Z and write the corresponding balanced balanced chemical equations.
Answer» SOLUTION :Since X is used in white washing, X is a `CA(HO)_(2)`, Y is a `CO_(2)` and Z is `CaCO_(3)` as it used for construction of monuments is `underset(X)(Ca(OH)_(2))+underset(Y)(CO_(2))tounderset(Z)(CaCO_(3))+H_(2)O` `CaCO_(3)+H_(2)O+CO_(2)toCa(HCO_(3))_(2)`

Discussion

14.	The componenets of compound are separated by physical processes.
Answer» Solution :False The CONSTITUENTS of a COMPOUND do not retain their properties and HENCE these cannot be SEPARATED by PHYSICAL methods.

Discussion

15.	Thecombining capacity of the metal which can exhibit more than one valency is called___________.
Answer» Solution :variable VALENCY Certain metals likeFe, Cu , Sn, etc ., exhibit more than ONE valencu their compounds CALLED variable valency EXAMPLE :`FeCl_(2),FeCl_(3)`

Discussion

16.	The colour change of CuSO_(4) solution can observed when it is made to react with
Answer» silver silver chloride solution zinc gold Solution :`underset("blue")(CuSO_(4))+Zntounderset("COLOURLESS")(ZnSO_(4))+CU`

Discussion

17.	The CO that is added up to the atmosphere due to the incomplete combustion of fuels can be decreased by the
Answer» usage of scrubber usage of electric precipitator. usage of catalytic convertor. increasing greenery. Solution :Catalytic convrtors consists of CERAMIC honey comb like structures with platinum catalyst spred out. The INCREASED surface are of the catalyst provides many REACTIVE SITES where the less OXIDIZED products like CO and NO are converted to `CO_(2)" and "N_(2)` which are released into th eatmosphere.

Discussion

18.	The chemical name of sand is
Answer» silicon sodium silicate silicon DIOXIDE calcium silicate Solution :The chemical name of SAND is silicon dioxide.

Discussion

19.	The chemical formula of rust is …………
Answer» SOLUTION :`Fe_(2)O_(3).XH_(2)O` The CHEMICAL formula of rust is `Fe_(2)O_(3).XH_(2)O`.

Discussion

20.	The chemical formula of plaster of Paris is _________
Answer» `CaSO_(4).1//2H_(2)O` `CaSO_(4)` `CaSO_(4).2H_(2)O` NONE Solution :`CaSO_(4).1//2H_(2)O` The chemical FORMULA of plaster of Paris is `CaSO_(4).1//2H_(2)O`.

Discussion

21.	The chemical composition of limestone is
Answer» CALCIUM carbonate calcium oxide calcium hydroxide calcium sulphate Solution :LIME STONE is common name of the compound calcium carbonate

Discussion

22.	The charge possessed by permanganate is the same as ___________ radical.
Answer» magnesium bisulphate sulphate potassium Solution :`MnO_(4)^(-) to` the CHARGE of permanganate is -1 which is same as bisulphate ion `(HSO_(4)^(-))`

Discussion

23.	The change of water into water vapour at 30^(@)C at slow rate is called ______.
Answer» SOLUTION :The CHANGE of water into water VAPOUR below `100^(@)C` at slow RATE is called evaporation.

Discussion

24.	The central part of the atom called nucleus accounts for the mass of an atom.
Answer» Solution :True Nucleus CONSISTS of both PROTONS and neutrons and it ACCOUNTS for the mass of the ATOM.

Discussion

25.	The atomicity of which among the following is the maximum ?
Answer» Helium Fluorine Ozone SULPHUR Solution :Sulphur has HIGHEST ATOMICITY of EIGHT.

Discussion

26.	The atomic numbers of the elements X, Y and Z are 2, 10 and 16, respectively. Identify the element which does not exist in monoatomic state.
Answer» X Z Y X and Y Solution :`{:("ELEMENT",X,Y,Z),("Valence SHELL",K,L,M),(,(1),(2),(3)),("Number of valence",,,),("electrons",2,8,6),("Element","He","Ne","S"):}` SULPHUR ( S)doesn ' t exist in monoatomic state due to its greater chemical reactivity.

Discussion

27.	The atomic number of three elements A, B and C are 10 , 18and 8respectively . Identify the element which is chemically reactive ?
Answer» A B C Both a and B Solution :`{:("Element","Atomic number","Electronic CONFIGURATION"),(""A," "10," "2_(,)8_(,)),(""B," "18," "2_(,)8_(,)8),(""C,""8," "2_(,)6):}` HENCE , 'C' is chemically reactive . A and B are chemiclly INERT because of stable octet configuration.

Discussion

28.	The atomic number and mass number of an element are 13 and 27 respectively. Find the number of neutrons.
Answer» SOLUTION :NUMBER of neutrons=27-13 =14

Discussion

29.	The atmosperic pressure is maxmum at ……… and found to be equal to ………
Answer» Solution :The atmospheric, PRESSURE is maximum at sea LEVEL and is found to be EQUAL to 760 MM of Hg.

Discussion

30.	The amount of heat energy required to increase the temperature of X g of water by 10^(@)C is found to be 15 cal. Calculate X.
Answer» 0.5 g 15 g 1.5 g 7.5 g Solution :The SPECIFIC heat of WATER is 1 `cal//g^(@)C`. `therefore` Heat REQUIRED for increasing `10^(@)C` temperature of X g water is 10 X cal. `therefore` 10X = 15 `therefore` X = 1.5 g

Discussion

31.	The amount of heat energy required to increase the temperature of 'X' g of water by 10 .^(@)C is found to be 15 cal. Calculate 'X'.
Answer» 0.5 g 15 g 1.5 g 7.5 g Solution :The SPECIFIC HEAT of water is 1 cal `g^(-1) .^(@)C^(-1)`. Therefore the amount of heat required is 1.5 cal for 15 for `10^(@)C` raise in temperature.

Discussion

32.	The amount of heat energy required to increase the temperature of 20 g of water by 1^(@)C is ______.
Answer» 10 cal 20 cal 15 cal 2 cal. Solution :Specific heat of water is 1 cal `G^(-1) .^(@)C`. Amount of heat ENERGY REQUIRED is `20 xx 1` = 20 cal. 1 cal - 1 g ? - 20 g = 20 cal

Discussion

33.	The …………. Alters the rate of reaction
Answer» SOLUTION :CATALYST The catalyst ALTERS the RATE of REATION.

Discussion

34.	Tellurium shows the properties of both metals and non-metals.
Answer» Solution :TRUE Tellurium is a metalloid and HENCE it show PROPERTIES of both metals and nonmetals.

Discussion

35.	Tartaric acid is one of the components in baking powder. What is its role?
Answer» SOLUTION :During BAKING, baking SODA present in baking powder induces bitter taste and YELLOW colour to breads and cakes due to the alkaline nature of its aqueous solution. To neutralize bitter taste of alkaline taste and to remove yellow colour, tartaricacid is USED.

Discussion

36.	Sunny and Bunny are neighbours staying in the same apartment. In summer vacation, one day they wanted to prepare some snaks for eating. During that process, the food material fell on the floorand the beautiful marble flooring became dirty. Sunny was afraid that his mother would scold him and in aa hurry, brought some acid to clean the floor. But, Bunny stopped him and said that it will spoil the flooring permanently. Why did Bunny say so? Give reason.
Answer» Solution :The major component of marble is `CaCO_(3)`. It being BASIC in NATURE, REACTS with an acid to FORM salt and water (neutralisation REACTION). Hence acids being reactive with marble, they cannot be used for cleaning marble flooring.

Discussion

37.	Sulphur dioxide on hydrolysis gives _________.
Answer» SOLUTION :Sulphur dioxide on HYDROLYSIS gives SULPHUROUS ACID.

Discussion

38.	Sugar gets charred when treated with conc. H_(2)SO_(4) . This is an example for __________
Answer» physicalchange. chemicalchange. simultaneous physical and chemical change. chemical combination reaction. Solution :When SUCROSE (sugar) is treated with conc .`H_(2)SO_(4)`coke is formed due to the removal of water molecules. `C_(12)H_(22)O_(11)overset("conc."H_(2)SO_(4))to12 C+11H_(2)O`

Discussion

39.	Sublimation of camphor is a physical change.
Answer» SOLUTION :True Sublimation of CAMPHOR is a PHYSICAL CHANGE.

Discussion

40.	Sublimation is the process of the conversion of a solid to its liquid state.
Answer» SOLUTION :FALSE Sublimation is the PROCESS of the CONVERSION of a solid to its GASEOUS state.

Discussion

41.	Sublimation is involved in _________ .
Answer» INCENSE stick and odonil. camphor and incense stick perfume and odonil. NAPHTHALENE BALLS and camphor. Solution :Naphthalene balls and camphor undergo sublimation

Discussion

42.	State and explain the anomalous expansion of water.
Answer» Solution :In GENERAL, solids posses greater densities than liquids. Therefore, for such liquids, the density DECREASES with an increase in temperature as the liquids expand on heating. However, in the case of water, it is different. Ice has lower density than water at the same temperature. As ice gets converted to water from `0^(@)C` its density increases and this trend continues upto `4^(@)C` temperature. Beyond `4^(@)C`, water shows NORMAL trend of decreases in density with increase in temperature. Therefore, density of water is maximum at `4^(@)C` (1g/cc). From `4^(@)C` to `0^(@)C`, water undergoes expansion while all other liquids undergo CONTRACTION. Since this trend is opposite to the normal trend, this is called anomalous expansion of water.

Discussion

43.	Spring water usually contains
Answer» dissolved salts minerals suspended impurities both 1 and 2 Solution :Spring WATER is USED for MEDICINAL PURPOSES because it contains dissolved salts, and minerals but not suspended impurities.

Discussion

44.	Specific heat of water is 1 cal g^(-1) .^(@)C^(-1)
Answer» SOLUTION :Specific heat capacity of water is 1 CAL. `g^(-1) .^(@)C^(-1)`

Discussion

45.	Sodium sulphate is a ______ salt.
Answer» SOLUTION :SODIUM SULPHATE is a NORMAL SALT.

Discussion

46.	Sodium is a very hard metal.
Answer» SOLUTION :FALSE Reason : Sodium is a very SOFT METAL.

Discussion

47.	Sodium floats on water.
Answer» SOLUTION :True As the density of SODIUN is less than that of WATER it FLOATS on water.

Discussion

48.	Sodium catches fire easily and chlorine is a harmful gas. But sodium shloride is indispensable in our daily meal. Give reasons.
Answer» Solution :SODIUM CHLORIDE is a compound. In compound, the constituents (sodium,chlorine) do not retain their properties and so we can TAKE NaCl in our DAILY MEAL.

Discussion

49.	Soda water contains excess……… in dissolved state.
Answer» `H_(2)` `CO_(2)` `N_(2)` `O_(2)` SOLUTION :Soda water contains excess of `CO_(2)` in dissolved state.

Discussion

50.	Smelling salt is
Answer» SODIUM chloride calcium CARBONATE AMMONIUM chloride ammonium carbonate Solution :Ammonium carbonate is SMELLING SALT.

Discussion

Explore topic-wise InterviewSolutions in Current Affairs.

Themetals with the least tensile strength is

The metallic compounds of which among the following metals is involved is involved in cloud seeding ?

The maximum number of electrons that can be accommodated in the outermost orbit is equal to _______.

The maximum number of electrons that can be accommodated in an orbit is equal to __________ where n is the number of orbits.

The maximum number of electrons in L shell is two.

The mass of an electron is _______ times that of mass of a proton.

The major component of naturalgas is _________

The inter conversion involved in usage of "odonil" in wash room is ________ .

The increase in the proportion of ………… in air leads to global warming.

The holes in the ozonosphere is due to the attack of a pollutant that is released from

The formulae ofa compound when a positiveradical with valency 2 and nedical with valency 1 combine is _______.

The conversion of a liquid to its solid state on cooling is called __________ .

The compounds X and Y combine to form a compound Z. 'Z' which is need for construction of monuments gets affected by acid rain. The compound X is used in white washing. Identify X, Y and Z and write the corresponding balanced balanced chemical equations.

The componenets of compound are separated by physical processes.

Thecombining capacity of the metal which can exhibit more than one valency is called___________.

The colour change of CuSO_(4) solution can observed when it is made to react with

The CO that is added up to the atmosphere due to the incomplete combustion of fuels can be decreased by the

The chemical name of sand is

The chemical formula of rust is …………

The chemical formula of plaster of Paris is _________

The chemical composition of limestone is

The charge possessed by permanganate is the same as ___________ radical.

The change of water into water vapour at 30^(@)C at slow rate is called ______.

The central part of the atom called nucleus accounts for the mass of an atom.

The atomicity of which among the following is the maximum ?

The atomic numbers of the elements X, Y and Z are 2, 10 and 16, respectively. Identify the element which does not exist in monoatomic state.

The atomic number of three elements A, B and C are 10 , 18and 8respectively . Identify the element which is chemically reactive ?

The atomic number and mass number of an element are 13 and 27 respectively. Find the number of neutrons.

The atmosperic pressure is maxmum at ……… and found to be equal to ………

The amount of heat energy required to increase the temperature of X g of water by 10^(@)C is found to be 15 cal. Calculate X.

The amount of heat energy required to increase the temperature of 'X' g of water by 10 .^(@)C is found to be 15 cal. Calculate 'X'.

The amount of heat energy required to increase the temperature of 20 g of water by 1^(@)C is ______.

The …………. Alters the rate of reaction

Tellurium shows the properties of both metals and non-metals.

Tartaric acid is one of the components in baking powder. What is its role?

Sulphur dioxide on hydrolysis gives _________.

Sugar gets charred when treated with conc. H_(2)SO_(4) . This is an example for __________

Sublimation of camphor is a physical change.

Sublimation is the process of the conversion of a solid to its liquid state.

Sublimation is involved in _________ .

State and explain the anomalous expansion of water.

Spring water usually contains

Specific heat of water is 1 cal g^(-1) .^(@)C^(-1)

Sodium sulphate is a ______ salt.

Sodium is a very hard metal.

Sodium floats on water.

Sodium catches fire easily and chlorine is a harmful gas. But sodium shloride is indispensable in our daily meal. Give reasons.

Soda water contains excess……… in dissolved state.

Smelling salt is