1214 + Interview Questions in Chemistry in Class 8 Page 8 InterviewSolution

351.	The poisonous gas, phosgene is prepared from _______ and ________ gases.
Answer» SOLUTION :`CO and Cl_(2)`.

Discussion

352.	The point when water changes into gaseous state.
Answer» SOLUTION :BOILING POINT

Discussion

353.	The particles are in constant random motion due to
Answer» inter-particle space inter-particle attraction KINETIC ENERGY heat Solution :kinetic energy

Discussion

354.	The outermost shell of an atom is known as its .................... and the electronsin it are known as ......................
Answer» SOLUTION :VALENCE SHELL, valence ELECTRONS

Discussion

355.	The number of valence electrons in ""_(4)X^(8) atom is
Answer» 1 2 3 4 Answer :B::C

Discussion

356.	The number of valence electrons in ""_(20)^(40)X is
Answer» 7 9 5 2 Answer :C::D

Discussion

357.	the number of oxygen atoms present in five molecules of ferrosoferric oxide is _____.
Answer» ANSWER :2O

Discussion

358.	The number of electrons present in each alpha-particle is
Answer» 2 3 0 1 Solution :`ALPHA`-particles are di-positivehelium ions. `therefore Z=2` A=4 NUMBER fo electrons=0 HELIUM atom contains two electrons. Its loses the two electrons to form `He^(+2)` ion.

Discussion

359.	The number of electrons in a di-positive ion of an element X is 18. If the mass number of X is 4 units more than twice the number of electrons of its ion, calculate of protons , electron and neutrons in X.
Answer» SOLUTION :(i) Number of electrons in correspondingneutral atom. (ii) CALCULATION of MASS number . (III) Calculation of number of neutrons from mass number and ATOMIC number. (iv) 20,20,20

Discussion

360.	The nucleus of an atom is considered to be electrically
Answer» positive negative neutral positive or negative Answer :A

Discussion

361.	The nature of _____ rays depends upon the nature of the gas in the discharge tube.
Answer» SOLUTION :ANODE RAYS

Discussion

362.	The names of the salts formed by the reaction of (i) Ca and HNO_3 Ca and H_2SO_3 are
Answer» (i) CALCIUM nitrate(II)Calium sulphate (i)Calcium NITRITE(ii) Calciumsulphite (i) Calcium nitrate(ii)Calcium sulphate (i) Calcium nitrate(ii)Calcium sulphate Answer :C

Discussion

363.	The molecules of a liquid possess _______type of motions.
Answer» SOLUTION :TRANSLATORY, ROTATORY, VIBRATORY

Discussion

364.	The molecular weight of a salt of oxy acid of chlorine of a dicalent metal whichcontains more number of oxygen atoms than its corresponding '-ic' acid is 239. What will the molecular weights of its (i) phosphate (ii) iodide(iii) bisulphatebe?
Answer» Solution :(i) Identification of NEGATIVE RADICAL of the given oxyacid. (ii)Identification of salt of an oxyacid from the given molecular weight. (iii)Calculation of ATOMIC weight of metaland identification of metal. (IV)Writing formulae of the DIVALENT metal with correspondingnegative radicals. (v)Calculation of molecular weights of the above salts. (vi)58

Discussion

365.	The molecular weight of a compound which contains a total number of five radicals is 160, then it is
Answer» `Ca_3P_2` `Fe_2O_3` `Al_2O_3` `Mg_3N_2` ANSWER :B::C

Discussion

366.	The molecular masses of sulphate and hydroxide of a metal M are 142 and 40 respectively. Calculate atomic mass and valency of the metal.
Answer» Solution :Let the valency of METAL be x and atomic meight be m. `:." Metal sulphate is "M^(+x)SO_4^(-2)rArrM_2(SO_4)_x` `:. " Metal HYDROXIDE is "M^(+x)OH_4^(-2)rArrM(OH)_x` `:." Molecular weight of metal sulphate is "` `2m+96x=142to(1)` Molecular weight of metal hudroxide is `m+17x=40` `rArr2m+34x=80to(2)` From (1) and (2) `rArr2m+34x=80` `((-)(-)(-))/(62x=62)` `rArrx=1` `:." From" (1)rArr2m+96(1)=142` `rArr2m=142-96=46rArrm=23` `:. " Valency and atomic weight of the metal are 1 and 23 RESPECTIVELY"`.

Discussion

367.	The molecular arrangement of a substance depends upon
Answer» TEMPERATURE concentration pressure All of the above Answer :C::D

Discussion

368.	The minimum temperature at which a substance burns in air is called ______.
Answer» SOLUTION :IGNITION TEMPERATURE

Discussion

369.	The maximum number of electrons present in 5th shell is ______.
Answer» ANSWER :50

Discussion

370.	The mass of which of the following fundamental particles is negligible ?
Answer» ELECTRONS Protons Neutrons Both (1) and (3) SOLUTION :MASS of electrons is negligible

Discussion

371.	The major components of CNG is ________
Answer» SOLUTION :METHANE

Discussion

372.	The main gas responsible for Greenhouse effect is
Answer» Oxygen Nitrogen Carbon monoxide Carbon DIOXIDE ANSWER :D

Discussion

373.	The layer of atmosphere that is just above the earth's surface is called ______.
Answer» THERMOSPHERE troposphere stratosphere mesosphere Answer :B

Discussion

374.	The kinetic energy of molecules ………………….with the increase in temperature.
Answer» SOLUTION :INCREASE

Discussion

375.	The isotope with zero neutrons is
Answer» protium deutuium tritium None of these Answer :A::C

Discussion

376.	The intermolecularforces of attraction between like molecules are called ________ and different molecules are called _______.
Answer» SOLUTION :COHESIVE FORCES, ADHESIVE forces.

Discussion

377.	The inter-particle force of attraction between the particles is maximum in
Answer» GASES liquids SOLIDS matter Solution :solids

Discussion

378.	The genuiness of a pearl can be verified by dipping it in lemon juice. Why ?
Answer» SOLUTION :REAL pearl is NOTHING butcalcium carbonate wihc gives EFFERVESCENCE of carbon dioxide when dipped in citric acid present in lemon JUICE. But imitation pearl is made up of plastic which does not give out carbon dioxide with lemon juice.

Discussion

379.	The gas liberated when concentrated sulphuric acid is reated with copper
Answer» `H_2` `SO_3` `H_2S` `SO_2` SOLUTION :CHOICE (4)

Discussion

380.	The fundamental particle present in anode rays produced by ""_(1)H^(1) is ______.
Answer» ANSWER :PROTON

Discussion

381.	The formula of th ephosphateof an element R is RPO_4, then the formulae of its hydroxide and sulphide respectively are _______are _______ .
Answer» `R(OH)_3andR_3S_2` `R(OH)_2andR_2S_3` `R(OH)_2andR_3S_2` `R(OH)_3andR_2S_3` ANSWER :C::D

Discussion

382.	The compounds SF_6 is named as ___________ .
Answer» SOLUTION :SULPHUR HEXAFLUORIDE

Discussion

383.	The compounds H_2O and D_2O follows Law of multiple proportions.
Answer» ANSWER :TRUE

Discussion

384.	The compounds formed when ammonia reacts with excess of chlorine are
Answer» `NH_4CL,HCL` `NCL_3,HCL` `N_2,HCL` `NH_4CL,NCL_3` SOLUTION :`2NH_3+6CL_2rarr2NCL_3+6HCL`

Discussion

385.	The compound which builds up the greenhouse effect is
Answer» CARBON monoxide GAS carbon carbon DIOXIDE none of these Solution :`CO_(2)` BUILDS up the GREEN house effect.

Discussion

386.	The compound of carbon used to soften hard water is ________
Answer» ANSWER :`Na_(2)CO_(3)`

Discussion

387.	The composition of lime mortar is _______
Answer» Solution :`CA(OH)_(2)`+ SAND + WATER

Discussion

388.	The combustion of sulphur and phosphorous is possible even in the presence of nitrous oxide and nitric oxide at high temperatures. Justifly
Answer» SOLUTION :(i) Changes that take place in `N_(2)OandNO` at HIGH TEMPERATURES. (ii) Products obtained from of the OXIDES of nitrogen at high temperature. (iii) REQUISITE for combustion.

Discussion

389.	The chemical X is a hydroxide of a djvalent metal. On treating this hydroxide with CO_2a milky white precipitate of Y is formed. The precipitate turns to colourless solution by the excess passage of CO_2 This colourless solution again gives milky white precipitate 'Y' on heating. Identify X and Y and also give -necessary equations.
Answer» SOLUTION :FORMULA of the WHITE precipitale.

Discussion

390.	The catalyst in the decomposition fo hydrogen peroxide is _______.
Answer» SOLUTION :`MnO_(2)`

Discussion

391.	The burning process in the synthetic material is quit slow and it does not get completely burnt easily. In the process it release lots of poisonous fumes into the atmosphere causing air pollution. How can this problem be solved?
Answer» Answer :The problem of air pollution and other ENVIRONMENT problems are CAUSED due to careless use of SYNTHETIC material such as plastic.

Discussion

392.	The brown coloured substance formed when steam is passed over red hot iron is
Answer» FERRIC oxide rust ferrosoferric oxide ferrous oxide Solution :The brown coloured substance formed when STREAM is PASSED over RED hot IRON is ferrosoferric oxide.

Discussion

393.	The boiling point of a solution is more than that of the pure solvent. Justify.
Answer» SOLUTION :(i) Vapour pressure of solution. (ii) Comparision of composition of solution to pure solvent. (iii) Forces acting in solution and pure solvent. ltbgt (iv) Relation between forces acting and vapour pressure. (V) Relation between vapour pressure and BOILING POINT.

Discussion

394.	The body temperature of a healthy person is around 98.4^(@)F. Justify.
Answer» Solution :Oxygen in the air is used for burning the fuel which GIVES ENERGY in the form of heat. In the same way oxygen inhaled by us is used INSIDE the TISSUES to break down the glucose and liberate energy in the form of heat. This liberated heat maintains the body TEMPERATURE at `98.4^(@)F`

Discussion

395.	The bleaching action of bleaching powder is due to thef ormation of
Answer» CHLORATE ION CHLORIDE ion CHLORITE ion hypochlorite ion Solution :`CaOCL_2+H_2OrarrCaCl_2+HOCL+HCL` `HOCLrarrH^++OCL^-` ltBRgt Hypochlorite ion

Discussion

396.	The beauty of Taj Mahal is being affected by
Answer» WATER pollution noise pollution air pollution all of them Answer :C

Discussion

397.	The bacterial COHVCISion ofnitrogen into nitrogen compounds is called "___________"
Answer» SOLUTION :NITROGEN FIXATION

Discussion

398.	The atoms of the same element may differ in the number of ________.
Answer» SOLUTION :NEUTRONS

Discussion

399.	The atomicity of the allotrpic form of oxygen is three.
Answer» ANSWER :1

Discussion

400.	That is a chemical combination reaction? Explain the different types of combination reactions.
Answer» SOLUTION :Cornbination of TWO or more DIFFERENT COMPONENTS

Discussion

Explore topic-wise InterviewSolutions in .

The poisonous gas, phosgene is prepared from _______ and ________ gases.

The point when water changes into gaseous state.

The particles are in constant random motion due to

The outermost shell of an atom is known as its .................... and the electronsin it are known as ......................

The number of valence electrons in ""_(4)X^(8) atom is

The number of valence electrons in ""_(20)^(40)X is

the number of oxygen atoms present in five molecules of ferrosoferric oxide is _____.

The number of electrons present in each alpha-particle is

The number of electrons in a di-positive ion of an element X is 18. If the mass number of X is 4 units more than twice the number of electrons of its ion, calculate of protons , electron and neutrons in X.

The nucleus of an atom is considered to be electrically

The nature of _____ rays depends upon the nature of the gas in the discharge tube.

The names of the salts formed by the reaction of (i) Ca and HNO_3 Ca and H_2SO_3 are

The molecules of a liquid possess _______type of motions.

The molecular weight of a salt of oxy acid of chlorine of a dicalent metal whichcontains more number of oxygen atoms than its corresponding '-ic' acid is 239. What will the molecular weights of its (i) phosphate (ii) iodide(iii) bisulphatebe?

The molecular weight of a compound which contains a total number of five radicals is 160, then it is

The molecular masses of sulphate and hydroxide of a metal M are 142 and 40 respectively. Calculate atomic mass and valency of the metal.

The molecular arrangement of a substance depends upon

The minimum temperature at which a substance burns in air is called ______.

The maximum number of electrons present in 5th shell is ______.

The mass of which of the following fundamental particles is negligible ?

The major components of CNG is ________

The main gas responsible for Greenhouse effect is

The layer of atmosphere that is just above the earth's surface is called ______.

The kinetic energy of molecules ………………….with the increase in temperature.

The isotope with zero neutrons is

The intermolecularforces of attraction between like molecules are called ________ and different molecules are called _______.

The inter-particle force of attraction between the particles is maximum in

The genuiness of a pearl can be verified by dipping it in lemon juice. Why ?

The gas liberated when concentrated sulphuric acid is reated with copper

The fundamental particle present in anode rays produced by ""_(1)H^(1) is ______.

The formula of th ephosphateof an element R is RPO_4, then the formulae of its hydroxide and sulphide respectively are _______are _______ .

The compounds SF_6 is named as ___________ .

The compounds H_2O and D_2O follows Law of multiple proportions.

The compounds formed when ammonia reacts with excess of chlorine are

The compound which builds up the greenhouse effect is

The compound of carbon used to soften hard water is ________

The composition of lime mortar is _______

The combustion of sulphur and phosphorous is possible even in the presence of nitrous oxide and nitric oxide at high temperatures. Justifly

The catalyst in the decomposition fo hydrogen peroxide is _______.

The burning process in the synthetic material is quit slow and it does not get completely burnt easily. In the process it release lots of poisonous fumes into the atmosphere causing air pollution. How can this problem be solved?

The brown coloured substance formed when steam is passed over red hot iron is

The boiling point of a solution is more than that of the pure solvent. Justify.

The body temperature of a healthy person is around 98.4^(@)F. Justify.

The bleaching action of bleaching powder is due to thef ormation of

The beauty of Taj Mahal is being affected by

The bacterial COHVCISion ofnitrogen into nitrogen compounds is called "___________"

The atoms of the same element may differ in the number of ________.

The atomicity of the allotrpic form of oxygen is three.

That is a chemical combination reaction? Explain the different types of combination reactions.

The poisonous gas, phosgene is prepared from _ and __ gases.

The intermolecularforces of attraction between like molecules are called __ and different molecules are called _.

The formula of th ephosphateof an element R is RPO_4, then the formulae of its hydroxide and sulphide respectively are _are _ .