908 + Interview Questions in Chemistry in Class 7

1.	Name two elements which have atomicity more than three .
Answer» <P> Solution :PHOSPHORUS `(P_(4))` and SULPHUR `(S_(8))` are the two ELEMENTS with ATOMICITY more than three.

Discussion

2.	Name two different kinds of plastics and their properties with examples.
Answer» Solution :Based on the thermal behaviour, plastic can be divided into two categories thermoplastics and THERMOSETTING PLASTICS. Thermoplastics : This type of plastic can be repeatedly PROCESSED by melting and subsequent solidification without undergoing any chemical change. Hence they can be reused. Examples ofthermoplastics are POLYETHYLENE, polyvinyl chloride, polystyrene, nylon, terelyene etc. Thermosetting plastics : Plastic of this variety cannot be softened by heating and THUS they cannot be reused. Examples of thermosetting plastics are urea formaldehyde, polyurethane, melamine, bakelite etc.

Discussion

3.	Name three organic compounds which are used as food materials. Mention their constituents and uses.
Answer» SOLUTION :

Discussion

4.	Name the substance added to water stored in reservoirs in regions with scanty rainfall. Give reason.
Answer» Solution :In regions with scanty RAINFALL, a substance called cetyl alcohol is SPRAYED on the water in reservoirs meant for STORAGE of large QUANTITIES of water. This reduces the rate of evaporation of water.

Discussion

5.	Name the soap commonly used for scrubbing floors.
Answer» SOLUTION :SCOURING soap is USED for scrubbing FLOORS.

Discussion

6.	Name the principlar products of cumbustion of glucose.
Answer» Solution :The principal products of combustion of GLUCOSE are CARBON dioxide and WATER.

Discussion

7.	Name the pollutants reponsible for the following effects. {:("(a) Reduction in intake of oxygen","(b) Cause of acid rain"),("(c) Green house effect","(d) Formation of smog"),("(e) Green house effect","(f) Problems of digestion"),("(g) Contamination of ground water","(h) Respiratory disorders"):}
Answer» Solution :(a) Carbon monoxide (b) Sulphur dioxide, nitogen oxide ( c) Carbon dioxide (d) Nitrogen oxides and suspended particulate matter. (e ) Cloro flouro carbons (F) LEAD releases from automobiles. (G)Fly ash (h) Sulphur dioxide

Discussion

8.	Name the most vital process where water takes part in the reaction in which one of the products is a supporter of life.
Answer» Solution :PHOTOSYNTHESIS is the most VITAL PROCESS in which water TAKES PART in the reaction.

Discussion

9.	Name the metal which is extensively used in a printed circuit board.
Answer» SOLUTION :COPPER metal is extensively USED in a PRINTED circuit board.

Discussion

10.	Name the metal which is extensively used in thermometers. Justify.
Answer» SOLUTION :Mercury is generally used in CLINICAL thermometer as it expands on heating has HIGH density and does not stick to CONTAINER.

Discussion

11.	Name thehardest compound and write one of its use ?
Answer» SOLUTION :SILICON CARBIDE is thehardest compound. It is USED in all KINDS of grinding wheels.

Discussion

12.	Name the gases which are respo0ndible for acid rain.
Answer» SOLUTION :The GASES that are reponsible for ACID RAIN are `NO_(2)," and "SO_(2)`.

Discussion

13.	Name the gas which absorbs ultraviolet rays.
Answer» SOLUTION :OZONE ABSORBS ULTRAVIOLET RAYS.

Discussion

14.	Name the factors which affect the rate of evaporation.
Answer» Solution :FACTORS affecting the RATE of evaporation are (i) SURFACE area , (ii) Temperature , (iii) HUMIDITY

Discussion

15.	Name the different layers of atmosphere ?
Answer» SOLUTION :The DIFFERENT layers of atmosphere are (a) TROPOSPHERE (b) Stratophere (c )Mesophere (d) THERMOSPHERE (e )Exosphere.

Discussion

16.	Name the dievice used to measure the atmosperic pressure.
Answer» SOLUTION :The device USED to MEASURE the atmopheric PRESSURE is barometer.

Discussion

17.	Name some agricultural practices which help in water management.
Answer» Solution :Adopting drip irrigation system in agricultural can EFFECTIVELY help minimize the USAGE of water for agriculturalpractices. Growing some PLANTS under plastic covers also MINIMIZES water loss as the water vapour condenses on the INNER surface of plastic cover and is given back to soil.

Discussion

18.	Name one compound of silver which is used for cloud seeding .
Answer» SOLUTION :SILVER iodide is used in CLOUD SEEDING.

Discussion

19.	Name of the salt formed by treating calcium oxide solution with nitric acid is ________ .
Answer» calcium NITRATE calcium nitrite calcium hydrogen nitrate calcium hydrogen nitrite SOLUTION :Calcium nitrate salt is formed by TREATING calcium oxide solution with nitric ACID.

Discussion

20.	Name of the radical PO_(4)^(-3) is ________.
Answer» SOLUTION :phosphate `PO^(-3)4`is called phosphate.

Discussion

21.	Name any two metals which are poor conductors of electricity
Answer» SOLUTION :Bismuth and TUNGSTEN are poor CONDUCTORS of electricity.

Discussion

22.	Name any two inert gases present in atmosphere
Answer» SOLUTION :The two inert gases PRESETN in ATMOSPHERE are argon and necn.

Discussion

23.	Name and formula of the salt formed by complete neutralization of aluminium hydroxide with ic acid of sulphur having four oxygen atoms is ______ and _____ respectively.
Answer» aluminium sulphite, `A1_(2)(SO_(3))_(3)` aluminium sulphate, `A1_(2)(SO_(4))_(3)` aluminium sulphate, `A1_(2)(SO_(3))_(3)` aluminium sulphite, `A1_(2)(SO_(4))_(3)` Solution :`2A1(OH)_(3) + 3H_(2)SO_(4) rarr UNDERSET("Aluminium sulphate")(A1_(2)(SO_(4))_(3) + 6H_(2)O)`

Discussion

24.	Mother took her two daughters Bhavani and Shivani to swimming pool in summer vacation. They both enjoyed swimming hours together. When they came out of swimming pool, both were shivering and fighting for the towel. Explain the reason for their shivering immediately after they came out of swimming pool.
Answer» Solution :Once we come out the swimming pool in SUMMER, water droplets present on the BODY undergo evaporation (slowly) which CAUSES cooling, as a RESULT we feel shivering.

Discussion

25.	Monobasis weak acid among the following is
Answer» carbonic acid oxalic acid ACETIC acid nitric acid Solution :Acetic acid on dissolution water gives only ONE `H^(+)` ion, it is a MONOBASIC acid. In acetic acid less than 30% of the molecules of it IONIZE in water to furnish `H^(+)` ions and hence it is a weak acid.

Discussion

26.	Mixture of iron fillings and sand can be separated by ________
Answer» Solution :MAGNETIC separation The mixture of IRON FILLING and SAND can be separated by magnetic separation

Discussion

27.	Meterits burn up in thermosphere.
Answer» SOLUTION :Meteories BURN up in MESOSPHERE.

Discussion

28.	Meteorites burn up in the mesophere but not in the thermosphere. It is due to
Answer» relatively thicker ATMOSPHERE in the mesophere. relatively thicker atmosphere in the theremosphere. very low temperatures in the mesophere. very low temperatures in the themosphere. Solution :Meteorites burn up in the mesosphere due to the presence of relatively thick atmosphere. Meteorites COLLIDE with molecules present in this layer and thus emit light called as SHOOTING STARS. While in the thermosphere, the thin atmosphere is not enough to produce FRICTION for the meteorites to burn.

Discussion

29.	Metals present in permutit are
Answer» Na and K Na and AL Al and K K and Al Solution :METALS present in PERMUTIT are Na and Al

Discussion

30.	Metals combine with other metals to form homogenous solid mixtures called ________
Answer» Solution :Alloys Metals COMBINE with other metals to FORM homogenous SOLID mixtures CALLED alloys.

Discussion

31.	Metals are highly ductile but non-malleable.
Answer» Solution :False METALS are highly DUCTILE and MALLEABLE.

Discussion

32.	Mercuric nitrate is a _________ salt (deliquescent/ efflorescent)
Answer» SOLUTION :MERCURIC NITRATE is a DELIQUESCENT SALT.

Discussion

33.	Mercuric nitrate is a deliquescent salt.
Answer» Solution :Deliquescent salts CHANGE into solution FORM due to the absorption of water from AIR. MERCURIC nitrate is a deliquescent salt.

Discussion

34.	Mention various methods of minimizing air pollution
Answer» Solution :Various methods of minimizing air pollution are as follows (i) Safe DISPOSAL of waste products. (ii) Equipments LIKE SCRUBBERS and precipitators are to be used in industries to precent the emissions of harmful gases. (III) Syntheses of ecofriendly chemicals. (iv) Arresting DEFORESTATION and incresing the plantation of greenery.

Discussion

35.	Mention various constituents of air and write their percentage by weight.
Answer» SOLUTION :The constitents of air and their percentages by weight are GIVEN below. Nitrogen-78.84% Oxygen-20.947% Argon-0.934% CARBON dioxide-0.033% Water vapour- 0 to 4 %

Discussion

36.	Mention two important uses of following acids and also mention the property exploited. (a) Hydrochloric acid (b) Nitric acid
Answer» Solution :`{:(,"Name of the acid",,"Uses","Property exploited"),((a),"Hydrochloric acid",(i),"Cleaning metal surfaces","Reaction of ACIDS with metal oxide"),(,,,"before tinning and galvanizing","coating."),(,,(ii),"Dyeing","HCI reacts with COMPLEX ORGANIC"),(,,,,"compounds and forms coloured compounds."),(,,(iii),"Preparation of glucose from ","HCI carries out hydrolysis of starch"),(,,,"starch","to glucose."),((b),"NITRIC acid",(i),"Fertilizers","Highly soluble NATURE of nitrate salts."),(,,(ii),"Explosives","TNT, TNG etc."),(,,(iii),"Purification of noble metals","Insoluble nature of Au and Pt in"),(,,,"(Au,Pt)",HNO_(3)):}`

Discussion

37.	Mention the ways of minimizing global warming.
Answer» Solution :DIFFERENT WAYS of minimizing global WARMING are as follows : (i) Reduction in the USAGE of FOSSIL fuels. (ii) Controlling deforstation (iii) Restrictiing the use of `CFC_(s)`.

Discussion

38.	Mention the uses of the following bases and mention the property exploited in those uses. (a) Sodium hydroxide (b) Calcium hydroxide (c) Magnesium hydroxide
Answer» Solution :Uses of bases `{:(,"NAME of base",,"USE","Property exploited"),((a),"Sodium hydroxide",(i),"Manufacture of soap","Reaction with oil"),(,"(caustic soda)and",(ii),"Paper pulp preparation","Reaction with hydrocarbons"),(,"potassium hydroxide",,,"of WOOD"),(,,(iii),"Synthetic fibres",),(,,(IV),"Manufacture of medicines",),((b),"Calcium hydroxide",(i),"Making mortar","Nectralization of acidity of soils"),(,,(ii),"Removal of hair from animal skin",),(,,(iii),"Spread on beetle leaves","Hardening of mortar on EXPOSURE to air"),(,,(iv),"Preparation bleaching powder",),(,,(v),"Preparation of metallic sodium",),(,,(vi),"Used as laboratory regent",),((c),"Magnesium hydroxide",,"Antacid","Neutralising action on excess"),(,,,,"HCI produced in the stomach"):}`

Discussion

39.	Mention the singnificance of water vapour in atmosphere.
Answer» Solution :Water vapour in the ATMOPHERE help in the FORMATION of fog, MIST, clouds ETC.

Discussion

40.	Mention the physical properties of aluminium.
Answer» Solution :Physical properties of aluminium (i) It possesses a silvery white lustre. (ii) It is highly malleable and ductile. (III) It is very good conductor of electricity (iv) It is very LIGHT in weight and corrosion resistant. (v) It is themost abundant metal in theearth's CRUST. (v) It is RELATIVELY soft when compared to other METALS. (vi) It is relatively soft when compared to other metals.

Discussion

41.	Mention the postulates and limitations of Dalton's atomic theory.
Answer» Solution :The main postulates of Dalton 's atomic theory are : (i)Matter is composed of tiny indivisible particles called atoms . Theycannot be created or destroyedor transformed into atoms of another element. (ii)Atoms of a givenelement are identical in all respects. (iii)Atoms of DIFFERENT elements aredifferent from each other in all respects. (iv)Atoms ofdifferent elements TAKE part in the chemical reaction and combine in a simple integral ratio to FORM compounds. (v) When elements REACT , the atoms may combine in more than one simple whole NUMBER ratio. Dalton 's atomic theory has been contradicted with the advancement of science and modified on the basisof further research and discoveries. Limitations of Dalton 's atomic theory (i)With the discovery ofsubatomic particles , thatis the electron , proton and neutron , it was concluded that atoms can be further divided. (ii)Discoveryofisotopes proved that atoms of the same element may possess different atomic weights, that atomsof same elementsmay not be identical in all respects . forexample isotopes of hydrogen namely , protium`(._(1)H^(1))` deuterium`(._(1)H^(2))` (iii)In some cases , atoms of different elements are found to have same mass number that is atoms of different elements may be identical . For example , calcium and argon are found to have same mass number.

Discussion

42.	Mention the percentage by volume of inactive and active components of atmospere
Answer» Solution :The precentage by volume of inactive and active COMPONENT of AIR are 78% and 21% respectively.

Discussion

43.	Mention the general methods of preparation of CO_(2)along with the chemical reactions.
Answer» Solution :General methods of preparation (a) Combustion: `CO_(2)` is released into atmophere when CARBON containing fuels like coal, natural gas ETC, are hurnt. Example: `C+O_(2)toCO_(2)+"heat"` `CH_(2)+3O_(2)toCO_(2)+2H_(2)O+"heat"` (b) Decomposition of metal carbonates: Metal carbonates on strong heating decompose to produce `CO_(2)` gas and corresponding metal oxides. Exceptions: Sodium carbonate and potassium carbonate. `"Example": {:(CaCO_(3)overset(Delta)(to)CaO+CI_(2)uarr),(CuCO_(3)overset(Delta)(to)CuO+CO_(2)uarr),(ZnCO_(3)overset(Delta)(to)ZnO+CO_(2)):}` ( c) Decomposition of metal hydrogen carbonates : Active metal hydrogen carbonate like sodium hydrogen carbonate commonly called baking SODA on heating produces `CO_(2)` gas along with the formation of correponding metal carbonate and water. `underset("carbonate")underset("or sodium hydrogen")underset("sodium BICARBONATE")(2NaHCO_(2))tounderset(("sodium carbonate"))(Na_(2)CO_(2)+H_(3)O+CO_(2))` (d) Action of dilute acids on metal carbonates and metal hydrogen carbonates: Metal corbonates and hydrogen carbonates when treated with dilute acids liberate `CO_(2)` gas along with the formation of corresponding salts. `NaCO_(3)+H_(2)SO_(4)toNa_(2)SO_(4)+H_(4)O+CO_(2)uarr` `Ca(CHO_(3))_(2)+2HNO_(3)toCa(NO_(3))_(2)+2H_(2)O+2CO_(2)uarr`

Discussion

44.	Mention the factors which indluence rusting of iton.
Answer» Solution :The FACTORS INFLUENCING the RUSTING are the presence of moistrue and OXYGEN.

Discussion

45.	Mention the factors on which the existence of matter in a particular state depends.
Answer» Solution :The TWO factors on which the existence of MATTER in a particular state DEPEND are temperature and pressure.

Discussion

46.	Mention the effects of acid rain
Answer» Solution :EFFECTS of acid rain are as follows : (i) The fertillity of the SOIL is lost or REDUCED. (ii) Crosp are dumaged. (iii) Pollutes water BODIES like revier, seas etc. (iv) Corrodes marble statues, monuments or buildings etc.

Discussion

47.	Mention the difference between filtrate and residue.
Answer» SOLUTION :In the filtration PROCESS, the clear liquid that is collected in the BEAKER is know as filtrate and the solid particles retained on the FILTER paper are known as residue.

Discussion

48.	Mention the appropriate term corresponding to the following sentences. (i) A solution obtained by passing carbon dioxide through sugar solution flavoured with desired substances. (ii) A substance formed by highly concentrated sugar solution flavoured with desired substances. (iii) A hard mass resembles the Portlandrock used by the people for the construction of building . (iv) The hardest compound of silicon, used in all kinds of grinding wheels. (v) A complex organic compound used as food, helps in development of cells , growth of the new cells and repair of damaged cells.
Answer» Solution :(i) Soft DRINKS (II) SYRUPS (III) PORTLAND cement (iv) Silicon carbide (v) Proteins

Discussion

49.	Mention the advanrage of existence of atmosphere.
Answer» Solution :(i) The air present in ARMOSPHERE is used for BREATHING. (II) The moistrure and dust particles present in air help in the FORMATION of clouds. (iii) The atmosphere protect us from harmful radiations.

Discussion

50.	Mention the action of oxygen with the elements sulphur, phosphorus, sodium and magnesium.
Answer» Solution :(i) Reaction with sodium (NA): Sodium reacts with `O_(2)` vigorously at room temperature to form sodium OXIDE `4Na_(2)+O_(2)to2Na_(2)O` (ii) Reaction with magnesium(Mg): Magnesium reacts with oxygen upon slight heating to form magnesium oxide `2Mg+O_(2)to2MgO` (iii) Reaction with sulphur: Sulphur when HEATED in an atmosphere of oxygen, burns to form sulphur DIOXIDE. `S+O_(2)toSO_(2)` (IV) Reation with phosphorus: When phosphorus is heated in an atmosphere of oxygen it burns to produce phosphorus pentioxide. `4P+5O_(2)to2P_(2)O_(5)`

Discussion

Explore topic-wise InterviewSolutions in Current Affairs.

Name two elements which have atomicity more than three .

Name two different kinds of plastics and their properties with examples.

Name three organic compounds which are used as food materials. Mention their constituents and uses.

Name the substance added to water stored in reservoirs in regions with scanty rainfall. Give reason.

Name the soap commonly used for scrubbing floors.

Name the principlar products of cumbustion of glucose.

Name the pollutants reponsible for the following effects. {:("(a) Reduction in intake of oxygen","(b) Cause of acid rain"),("(c) Green house effect","(d) Formation of smog"),("(e) Green house effect","(f) Problems of digestion"),("(g) Contamination of ground water","(h) Respiratory disorders"):}

Name the most vital process where water takes part in the reaction in which one of the products is a supporter of life.

Name the metal which is extensively used in a printed circuit board.

Name the metal which is extensively used in thermometers. Justify.

Name thehardest compound and write one of its use ?

Name the gases which are respo0ndible for acid rain.

Name the gas which absorbs ultraviolet rays.

Name the factors which affect the rate of evaporation.

Name the different layers of atmosphere ?

Name the dievice used to measure the atmosperic pressure.

Name some agricultural practices which help in water management.

Name one compound of silver which is used for cloud seeding .

Name of the salt formed by treating calcium oxide solution with nitric acid is ________ .

Name of the radical PO_(4)^(-3) is ________.

Name any two metals which are poor conductors of electricity

Name any two inert gases present in atmosphere

Name and formula of the salt formed by complete neutralization of aluminium hydroxide with ic acid of sulphur having four oxygen atoms is ______ and _____ respectively.

Monobasis weak acid among the following is

Mixture of iron fillings and sand can be separated by ________

Meterits burn up in thermosphere.

Meteorites burn up in the mesophere but not in the thermosphere. It is due to

Metals present in permutit are

Metals combine with other metals to form homogenous solid mixtures called ________

Metals are highly ductile but non-malleable.

Mercuric nitrate is a _________ salt (deliquescent/ efflorescent)

Mercuric nitrate is a deliquescent salt.

Mention various methods of minimizing air pollution

Mention various constituents of air and write their percentage by weight.

Mention two important uses of following acids and also mention the property exploited. (a) Hydrochloric acid (b) Nitric acid

Mention the ways of minimizing global warming.

Mention the uses of the following bases and mention the property exploited in those uses. (a) Sodium hydroxide (b) Calcium hydroxide (c) Magnesium hydroxide

Mention the singnificance of water vapour in atmosphere.

Mention the physical properties of aluminium.

Mention the postulates and limitations of Dalton's atomic theory.

Mention the percentage by volume of inactive and active components of atmospere

Mention the general methods of preparation of CO_(2)along with the chemical reactions.

Mention the factors which indluence rusting of iton.

Mention the factors on which the existence of matter in a particular state depends.

Mention the effects of acid rain

Mention the difference between filtrate and residue.

Mention the advanrage of existence of atmosphere.

Mention the action of oxygen with the elements sulphur, phosphorus, sodium and magnesium.

Name and formula of the salt formed by complete neutralization of aluminium hydroxide with ic acid of sulphur having four oxygen atoms is __ and _ respectively.