94420 + Interview Questions in Chemistry in Class 12

1.	Heat of formation of H_2O(g) at 1 atm and 25^@C is -243 kJ. triangleE for the reaction, H_2(g)+1/2O(g)rarrH_2O(g) at 25^@C is
Answer» 241.8 KJ `-241.8 kJ` `-243 kJ` 243 kJ Answer :B

Discussion

2.	Heterolysis of propane gives:
Answer» Methyl and ETHYL FREE radicals Methylium CATION and ethyl ANION Methyl anion and ethylium cation Methylium and ethylium cations Answer :C

Discussion

3.	Heat of formation of CO_(2)(g), H_(2)O(l) and CH_(4)(g) are - 94.0, - 68.4 and -17.9 kcal respectively. The heat of combustion of methane is
Answer» `- 212.9` kcal `- 136.8` kcal `- 304.3` kcal `- 105.2` kcal Solution :Find`DeltaH" for "CH_(4(g))+2O_(2(g))rarrCO_(2(g))+2H_(2)O_((L))`

Discussion

4.	Heat of formation of CH_(4) are: If given heat: C(s)+ O_(2)(g) rarr CO_(2) (g) ""DeltaH =-394 KJ 2H_(2) (g)+ O_(2)(g) rarr 2H_(2)O(l) rarr 2H_(2)O(l) ""DeltaH =-394 KJ CH_(4)(g) + 2O_(2)(g) rarr CO_(2)(g) + 2H_(2)O(l) "" DeltaH =- 394 KJ
Answer» `-70 KJ` `-16.7 Kcal` `-244 KJ` `-50 Kcal` Solution :`(1) + (2)-(3)` `DeltaH_("REACTION") =-394 -568+892=-70 KJ` `""=-16.607Kcal.`

Discussion

5.	Heterolysis of carbon-chlorine bond produces:
Answer» TWO FREE radicals Two CARBONIUM ions Two carbonium ONE CATION and one anion Answer :D

Discussion

6.	Heat of formation of CO_(2)(g), H_(2)O(l) and CH_(4)(g) are -94.0, -68.4 and -17.9 kcal respectively. The heat of combustion of methane is
Answer» `-212.9` KCAL `-136.8` Kcal `-304.3` Kcal `-105.2` Kcal ANSWER :A

Discussion

7.	Heat of formation in the reactionH_(2)+Cl_(2)rarr2HCl+44 kcal is
Answer» 44 KCAL 44000 kcal 22 kcal 11 kcal Solution :`DeltaH_(F)=(44)/(2)kcal=22 kcal`.

Discussion

8.	Heterolysis of C-Br bond produces
Answer» two carbanions two carbocations two free radicals one CATION and one anion Solution :HETEROLYSIS leads the FORMATION of cation and anion. In which carbon acquired `delta^(+)` charge and Br acquired `delta^(+)` charge becauise of more electronegativity.

Discussion

9.	Heat of dissociation of benzene to elements is 5535 KJ mol^(-1). The bond enthalpies of C - C, C = C and C - H are 347.3, 615.0 and 416.2 KJ respectively. Resonance energy of benzene is
Answer» 1.51 KJ 15.1 KJ 151 KJ 1511 KJ SOLUTION : `Delta H_("Calculated")=Sigma (B.E.)_(R )-Sigma (B.E.)_(P)` `Delta H_("Cal")=[3XX(B.E.)_(C=C)+6XX(B.E.)_(C-H)+3xx(B.E.)_(C-C)]-0` `Delta H_("Cal")=[3xx(615)+6xx(416.2)+3xx(347.33)]` `Delta H_("Calculated")=5384.1 KJ mol^(-1)` RESONANCE energy `=Delta H_("Observed")-Delta H_("Calculated")` `=5535-5384.1` Resonance energy `~= 151 KJ`

Discussion

10.	Heterolysis of a carbon-chloride bond produces
Answer» One CATION and one ANION Two carbonium ION Two carbon ions Two free RADICALS Answer :A

Discussion

11.	Heat of combustion of gaseous isoprene (C_(5) H_(8)) CH_(2) = CH - C = underset(CH_(3))underset(\|)(C) H_(2) to CO_(2) (g)& H_(2) O (l)is -3186 kJ/mole . Calculate the heat of formation and compare with bond energies. Calculate the resonance energy of isoprene. Given : Delta_(f) H (CO_(2) , g) = -393 .5kJ/mol , Delta_(f) H (H_(2) O , l) = -285.84 kJ/mol Bond energies ofC- H , C - C& C = C are 413 , 348 and 615 kJ . Heat of atomization of carbon and H_(2) are 718.4 and 435.8
Answer» SOLUTION :`-30.06` kJ/mol

Discussion

12.	Heterocyclic (six membered secondary amines possible for C_(6)H_(13)N
Answer» SOLUTION :

Discussion

13.	Heat of combustion of methane is - 800 kJ. What is the heat of combustion for4 xx 10^(-4) kg of methane ?
Answer» `-800 kJ` `-3.2xx10^(4) kJ` `-20kJ` `-1600 kJ` SOLUTION :`underset(16g)(CH_(4)+2O^(2) to CO_(2) +2H_(2)O,DeltaH_(C)=-800kJ` `:'` Heatof COMBUSTION of ` 4xx10^(-4)` kg `CH_(4)` will be `=-(800x4xx10^(-4))/(16xx10^(-3))` `=-20 kJ`

Discussion

14.	Hess's law of heat of summation is based on law of conservation of energy. It has found significance in deriving heats of many reactions which either do not take place or if take place, than other side reactions also accompany it. For example heat of reaction for C + (1)/(2) O_(2) toCO can not be studied directly as it occurs with simultaneous reaction of oxidation of CO to CO_(2). Bond energy is referred as heat enthalpy when a bond is broken to produce isolated gaseous atoms. In case of breaking up of bonds between unlike atoms e.g., C – H bond in CH_(4), bond energy is referred as average bond energy as four C – H bonds are broken up. If C + (1)/(2) O_(2) to CO_((g)) , Delta H= -110 kJ . C + H_(2)O_((g)) to CO_((g)) + H_(2) (g) , Delta H = 132 kJThe mole composition of mixture of steam and O_(2) and steam on being passed over coke at 1273 K so that temperature remains constant is :
Answer» `0.6 : 1` `1.67 : 1` `0.3 : 1` `0.4 : 1` ANSWER :B

Discussion

15.	Heat of combustion of ethyl alcohol is 325 kcal and that of acetic acid is 209.5 kcal. Calculate the heat evolved in the following reaction : C_(2)H_(5)OH+O_(2) to CH_(3)COOH+H_(2)O
Answer» Solution :Given that, (i) `C_(2)H_(5)OH(l)+3O_(2)(g) to 2CO_(2)(g)+3H_(2)O(g),DeltaH=-325kcal.` (ii) `CH_(3)COOH(l)+2O_(2)(g) to 2CO_(2)(g)+2H_(2)O(g),` `DeltaH=-209.5kcal` `C_(2)H_(5)OH` in EQN. (i) and in the required equation is on the same sides, wheras `CH_(3)COOH` in Eqn. (ii) and in the required equation is on the OPPOSITE sides. Hence, applying `[Eqn. (i)- Eqn. (ii)]`, we get, `C_(2)H_(5)OH(l)+3O_(2)(g)-CH_(3)COOH(l)-2O_(2)(g) to ` `2CO_(2)(g)+3H_(2)O(l)-2CO_(2)(g)-2H_(2)O(l),` `DeltaH=-325-(-209.5)` or `C_(2)H_(5)OH(l)+O_(2)(g) to CH_(3)COOH(l)+H_(2)O(l),` DeltaH=-115.5kcal`

Discussion

16.	heat of combustion of gaseous compounds A(molar mass =16) B(molar mass=28) C(molar mass=30) and D(molar mass=40) are-890 ,-1411, -1560 and-1900 kJ/molerespectively.Which has the highest calorific fuel(J/g)?
Answer» A B C D Answer :A

Discussion

17.	Hess's law of heat of summation is based on law of conservation of energy. It has found significance in deriving heats of many reactions which either do not take place or if take place, than other side reactions also accompany it. For example heat of reaction for C + (1)/(2) O_(2) toCO can not be studied directly as it occurs with simultaneous reaction of oxidation of CO to CO_(2). Bond energy is referred as heat enthalpy when a bond is broken to produce isolated gaseous atoms. In case of breaking up of bonds between unlike atoms e.g., C – H bond in CH_(4), bond energy is referred as average bond energy as four C – H bonds are broken up. Heat of dissociation of CH_(4) and C_(2) H_(6) are 360 and 620 kcal mol^(-1) . The C-C bond energy would be : -
Answer» 60 kcal 80 kcal 100 kcal 40 kcal Answer :B

Discussion

18.	Heat of combustion of C(s), H_2(g) and CH_4 (g) respectively are -94, -68 and -213 kcal/mol, thendeltaH for the reacton [C(s) +2H_2(g) → CH_4(g)] is
Answer» -17 kcal -34 kcal -886 kcal -51 kcal Answer :1

Discussion

19.	Heat of combustion of CH_4, C_2H_4, C_2H_6 are-890, -1411 and -1560 kJ/mol respectively. Which has the lowest calorific fuel value in kJ/g:
Answer» `CH_4` `C_2H_4` `C_2H_6` All same Answer :B

Discussion

20.	Hess's law of heat of summation is based on law of conservation of energy. It has found significance in deriving heats of many reactions which either do not take place or if take place, than other side reactions also accompany it. For example heat of reaction for C + (1)/(2) O_(2) toCO can not be studied directly as it occurs with simultaneous reaction of oxidation of CO to CO_(2). Bond energy is referred as heat enthalpy when a bond is broken to produce isolated gaseous atoms. In case of breaking up of bonds between unlike atoms e.g., C – H bond in CH_(4), bond energy is referred as average bond energy as four C – H bonds are broken up. Which of the following statements are correct : (1)The dissociation of bond is always endothermic (2) The formation of a bond is always exothermic. (3)Heat of formation of an atom = (1)/(2)xx bond energy like atoms covalent bond (4) The heat enthalpy change in a chemical reaction is equal but opposite to the heat enthalpy if reaction is reversed. (5) Hess's law can be verified experimentally.
Answer» 1 , 2 , 3 , 4 1 , 2 , 3 , 4 ,5 2, 3 , 4 , 5 3 , 4 ,5 Answer :A

Discussion

21.	Heat of combustion of carbon monoxide is -283.5 kJ/mole. The heat released when 55 g of carbon dioxide formed from carbon monoxide is
Answer» 283.5 kJ 324.2 kJ 354.4 kJ 385.5 kJ Answer :D

Discussion

22.	Heat of combustion of A(s) is -10" kcal mol"^(-1) and that of B is-"15 kcal mol"^(-1). On combustion of 3 mol of A and x mol of B , the heat released "105 kcal ". What is the value of x ?
Answer» ANSWER :5

Discussion

23.	Heat of combustion of a substance
Answer» Is ALWAYS positive Is always negative Is EQUAL to heat of formation Nothing can be SAID without reaction Answer :B

Discussion

24.	Heat of combustion is also known as _____.
Answer» ANSWER :ENTHALPY of COMBUSTION

Discussion

25.	Heat of combustion DeltaH ofCH_(4), C_(2)H_(6), C_(2)H_(4) and C_(2)H_(2)gases are - 212.8, - 373.0, - 337.0and - 310.5 kcal respectively at the same temperature. The best fuel among these gases is
Answer» `CH_(4)` `C_(2)H_(6)` `C_(2)H_(4)` `C_(2)H_(2)` Solution :`CH_(4)` is the BEST fuel because its CALORIFIC value`=(-212.8)/(16)=-13.3 kcal//g` is higher among the other GASES.

Discussion

26.	Hesss law of heat of summation includes
Answer» INITIAL REACTANTS only initial reactants and FINAL PRODUCTS final products only intermediates only Answer :B

Discussion

27.	Heat of adsorption is low hence physical adsorption occurs at .... .............
Answer» SOLUTION :LOW TEMPERATURE

Discussion

28.	Hess's law of constant heat summation is based on
Answer» `E=mc^(2)` CONSERVATION of MASS First law of THERMODYNAMICS None of the above Solution :HESS's law is an APPLICATION of first law of thermodynamics.

Discussion

29.	Hess's law is used in the determination of:
Answer» HEAT of recation Heat of transition Heat of formation All of these Answer :D

Discussion

30.	Heat of atomization of zinc is lowest among 3d block elements due to
Answer» STRONGER metallic bond in ZINC (n-1) d ELECTRONS do not involve in bonding (n-1) d electrons involve in bonding LARGER size of zinc Answer :B

Discussion

31.	Hess's law of constant heat summation is an application of:
Answer» KIRCHHOFF's LAW First law of thermodynamic Second law of thermodynamics Third law of thermodynamics Answer :B

Discussion

32.	Heat of adsorption is greater for chemisorptions than physisorption. Why?
Answer» Solution :In chemical adsorption, gas molecules are held to the SURFACE by FORMATION of chemical bonds. Since strong bond is formed, nearly 400 KJ / mole is given out as heat of absorption. Whereas in physical adsorption, physical forces LIKE van der Waals force of attraction exist between adsorbent and adsorbate. The various other forces that can cause physical adsorption are (i) dipole - dipole INTERACTION (ii) Dispersion forces As these forces are weak, heat of adsorption is low, hence physical adsorption occurs at low TEMPERATURES.

Discussion

33.	Hess's law is related to:
Answer» CHANGE in HEAT during of reaction Rates of reaction equilibrium constant influence of PRESSURE on VOLUME of a gas Answer :A

Discussion

34.	Heat liberated when 100 mL of 1N NaOH is neutralised by 300 ml of 1N HCl
Answer» A) 11.46 kJ B )5.73 kJ C) 22.92 kJ D) 17.19 kJ Solution :1000 ml of N NaOH contains= 40G of NaOH`-=`1 mole 100 ml of N NaOH will CONTAIN `=0.4gm" "NaOH-=(1)/(10)`mole Now, `underset("0.1 mole")(OH^(-))+underset("0.1 mole")(H^(+)) to underset("0.1 mole")(H_(2)O)` `because` When 1 mole of `H_(2)O` is formed, the heat produced =57.3 kJ `therefore` When 0.1 mole `H_(2)O` is formed, the heat produced `=57.3xx0.1=5.73kJ`

Discussion

35.	Hess's law is based on
Answer» law of CONSERVATION of mass law of conservation of energy first law of thermodynamics none of these Solution :HESS's law is BASED upon law of conservation of energy.

Discussion

36.	Heat islands are produced due to
Answer» AIR POLLUTION Land pollution Water pollution All of the above Answer :A

Discussion

37.	Hess's law is applicable for the determination of heat of
Answer» reaction formation transition All ofthese Answer :D

Discussion

38.	Heat given to a system under isochoric process is equal to:
Answer» W `q_p` `TRIANGLEE` `TRIANGLEH` ANSWER :A

Discussion

39.	Heat evolved in the reaction,H_2+Cl_2rarr2HCl is 182 kJ. Bond energies of H-H and Cl-Cl are 430 and 242 kJ/mol respectively. The H-Cl bond energy is:
Answer» `245 KJ mol^-1` `427 kJ mol^-1` `336 kJ mol^-1` `154 kJ mol^-1` ANSWER :A

Discussion

40.	Heat exchanged in a chemical reaction at constant temperature and pressure is called
Answer» <P>INTERNAL energy Enthalpy Entropy Free energy Solution :`DeltaH=q_(p)`.

Discussion

41.	Hess's law deals with
Answer» CHANGE in HEAT of reaction rate of reaction equilibrium constant influence of PRESSURE on VOLUME of a gas Answer :A

Discussion

42.	Heat energy change during the chemical reaction, CO+1//2O_2rarrCO_2 is known as:
Answer» HEAT of COMBUSTION of CO LATENT heat of `CO_2` Latent heat of vaporisation Heat of FORMATION of `CO_2` ANSWER :A

Discussion

43.	Hess law is applicable for the determination of heat of
Answer» REACTION Formation Tansition All of these Answer :D

Discussion

44.	Heat capacity (C_(p)) is an extensive property but specific heat (C) is an intensive property. What will be the relation between C_(p) and C for 1 mole of water?
Answer» <P>`+4.18JK^(-1)` `-4.18JK^(-1)` `-75.3JK^(-1)` `+75.3JK^(-1)` Solution :For water, MOLAR HEAT capacity, `C_(p)=18xx`specific heat C Specific heat, `C=4.18Jg^(-1)K^(-1)` (for water) heat capacity, `C_(p)=18xx4.18JK^(-1)` `=75.24JK^(-1)=75*3JK^(-1)`

Discussion

45.	Heroine is a …………….. Analgesic.
Answer» SOLUTION :NARCOTIC.

Discussion

46.	Heat capacity at constant temperature and constant pressure for H_(2) is
Answer» 5 cal `mol^(-1)K^(-1)` 7 cal `mol^(-1)K^(-1)` 8 cal `mol^(-1)K^(-1)` `oo` Answer :D

Discussion

47.	Heroin is derivative of
Answer» CAFFEINE MORPHINE Cocaine Nicotine Solution :HEROIN is acyl DERIVATIVE of morphine.

Discussion

48.	Heametite is an ore of
Answer» Co Ni Mn Fe Answer :D

Discussion

49.	Heroin is acctyl derivative of
Answer» caffeine cocaine nicotine MORPHINE. Solution :HEROIN is DIACETYL DERIVATIVE of morphine.

Discussion

50.	Heart attacks can be checked by using the enzyme.............
Answer» SOLUTION :STREPTOKINASE

Discussion

Explore topic-wise InterviewSolutions in Current Affairs.

Heat of formation of H_2O(g) at 1 atm and 25^@C is -243 kJ. triangleE for the reaction, H_2(g)+1/2O(g)rarrH_2O(g) at 25^@C is

Heterolysis of propane gives:

Heat of formation of CO_(2)(g), H_(2)O(l) and CH_(4)(g) are - 94.0, - 68.4 and -17.9 kcal respectively. The heat of combustion of methane is

Heat of formation of CH_(4) are: If given heat: C(s)+ O_(2)(g) rarr CO_(2) (g) ""DeltaH =-394 KJ 2H_(2) (g)+ O_(2)(g) rarr 2H_(2)O(l) rarr 2H_(2)O(l) ""DeltaH =-394 KJ CH_(4)(g) + 2O_(2)(g) rarr CO_(2)(g) + 2H_(2)O(l) "" DeltaH =- 394 KJ

Heterolysis of carbon-chlorine bond produces:

Heat of formation of CO_(2)(g), H_(2)O(l) and CH_(4)(g) are -94.0, -68.4 and -17.9 kcal respectively. The heat of combustion of methane is

Heat of formation in the reactionH_(2)+Cl_(2)rarr2HCl+44 kcal is

Heterolysis of C-Br bond produces

Heat of dissociation of benzene to elements is 5535 KJ mol^(-1). The bond enthalpies of C - C, C = C and C - H are 347.3, 615.0 and 416.2 KJ respectively. Resonance energy of benzene is

Heterolysis of a carbon-chloride bond produces

Heterocyclic (six membered secondary amines possible for C_(6)H_(13)N

Heat of combustion of methane is - 800 kJ. What is the heat of combustion for4 xx 10^(-4) kg of methane ?

Heat of combustion of ethyl alcohol is 325 kcal and that of acetic acid is 209.5 kcal. Calculate the heat evolved in the following reaction : C_(2)H_(5)OH+O_(2) to CH_(3)COOH+H_(2)O

heat of combustion of gaseous compounds A(molar mass =16) B(molar mass=28) C(molar mass=30) and D(molar mass=40) are-890 ,-1411, -1560 and-1900 kJ/molerespectively.Which has the highest calorific fuel(J/g)?

Heat of combustion of C(s), H_2(g) and CH_4 (g) respectively are -94, -68 and -213 kcal/mol, thendeltaH for the reacton [C(s) +2H_2(g) → CH_4(g)] is

Heat of combustion of CH_4, C_2H_4, C_2H_6 are-890, -1411 and -1560 kJ/mol respectively. Which has the lowest calorific fuel value in kJ/g:

Heat of combustion of carbon monoxide is -283.5 kJ/mole. The heat released when 55 g of carbon dioxide formed from carbon monoxide is

Heat of combustion of A(s) is -10" kcal mol"^(-1) and that of B is-"15 kcal mol"^(-1). On combustion of 3 mol of A and x mol of B , the heat released "105 kcal ". What is the value of x ?

Heat of combustion of a substance

Heat of combustion is also known as _____.

Heat of combustion DeltaH ofCH_(4), C_(2)H_(6), C_(2)H_(4) and C_(2)H_(2)gases are - 212.8, - 373.0, - 337.0and - 310.5 kcal respectively at the same temperature. The best fuel among these gases is

Hesss law of heat of summation includes

Heat of adsorption is low hence physical adsorption occurs at .... .............

Hess's law of constant heat summation is based on

Hess's law is used in the determination of:

Heat of atomization of zinc is lowest among 3d block elements due to

Hess's law of constant heat summation is an application of:

Heat of adsorption is greater for chemisorptions than physisorption. Why?

Hess's law is related to:

Heat liberated when 100 mL of 1N NaOH is neutralised by 300 ml of 1N HCl

Hess's law is based on

Heat islands are produced due to

Hess's law is applicable for the determination of heat of

Heat given to a system under isochoric process is equal to:

Heat evolved in the reaction,H_2+Cl_2rarr2HCl is 182 kJ. Bond energies of H-H and Cl-Cl are 430 and 242 kJ/mol respectively. The H-Cl bond energy is:

Heat exchanged in a chemical reaction at constant temperature and pressure is called

Hess's law deals with

Heat energy change during the chemical reaction, CO+1//2O_2rarrCO_2 is known as:

Hess law is applicable for the determination of heat of

Heat capacity (C_(p)) is an extensive property but specific heat (C) is an intensive property. What will be the relation between C_(p) and C for 1 mole of water?

Heroine is a …………….. Analgesic.

Heat capacity at constant temperature and constant pressure for H_(2) is

Heroin is derivative of

Heametite is an ore of

Heroin is acctyl derivative of

Heart attacks can be checked by using the enzyme.............