Q.1
If enthapies of formation of C2H4(g), CO2(g) and H2O(l) at 25° and 1atm pressure are 52, -394, and -286kJ/mol, the enthalpy of combusion pf ethene is equl to [AIPMT 1995]
  • a) -141.2 kJ/mol
  • b) -1412 kJ/mol
  • c) +14.2 kJ/mol
  • d) +1412 kJ/mol
Q.2
Given that C(s) + O2(g) → CO2(g), ΔH&dge = -x kJ 2CO(g) + O2 → 2CO2(g), ΔH&dge = -ykJ The enthalpy of formation of carbon monoxide will be .. [ AIPMT 1997]
  • a) y - 2x
  • b) 2x-y
  • c) (y-2x)/2
  • d) (2x-y)/2
Q.3
Enthalpy of the reaction, CH4 + ½O2 → CH3OH is negative. if enthalpy of combustion of CH4 and CH3OH are 'x' and 'y' respectively, then which relation is correct? [ AIPMT 2001]
  • a) x > y
  • b) x < y
  • c) x = y
  • d) x ≥ y
Q.4
For which one of the following equations ΔH°r equal to ΔH°f for the product? [ AIPMT 2003]
  • a) Xe(g) + 2F2(g) → XeF4(g)
  • b) 2CO(g) + O2(g) → 2CO2(g)
  • c) N2(g) + O3(g) → N2O3(g)
  • d) CH4(g) + 2Cl2 → CH2Cl2(l) + 2HCl(g)
Q.5
If the bond energies of H-H, Br-Br and H-Br are 433, 192, and 364 kJmol- respectively, then ΔH° for the reaction H2(g) + Br2(g) → 2HBr(g) is .... [ AIPMT 2004]
  • a) -261 kJ
  • b) +103kJ
  • c) +261kJ
  • d) -103 kJ
Q.6
A reaction occurs spontaneously if ... [ AIPMT 2005]
  • a) TΔS < ΔH and both ΔH and ΔS are +ve
  • b) TΔS > ΔH and both ΔH and ΔS are +ve
  • c) TΔS = ΔH and both ΔH and ΔS are +ve
  • d) TΔS > ΔH and ΔH is +ve and ΔS are -ve
Q.7
Which of the following pairs of a chemical reaction is certain to result in a spontaneous reaction? [ AIPMT 2005]
  • a) Exothermic and decreasing disorder
  • b) Endothermic and increasing disorder
  • c) Exothermic and increasing disorder
  • d) Endothermic and decreasing disorder
Q.8
Standard enthalpy of vaporization ΔvapH° for water at 100°C is 40.66 kJ mole-The internal energy of vaporisation of water at 100&dgeC (inkJ mol-1) is (assume water vapour to behace like an ideal gas)[ AIPMT 2012]
  • a) +37.56
  • b) -43.76
  • c) +43.76
  • d) +40.66
Q.9
The enthalpy of fusion of water is 1.435 kcal/mol. the molar entropy change for the melting of ice at 0°C is [ AIPMT 2012]
  • a) 10.52 cal/mol K
  • b) 21.04 cal/mol K
  • c) 5.260 cal/mol K
  • d) 0.526 cal/mol k
Q.10
Given C + 2S → CS2 , ΔHfo=+ 117.0 kJ/molC+ O2 → CO2 , ΔHfo=- 393.0 kJ/molS+ O2 → SO2 , ΔHfo=- 287.0 kJ/mol The heat of combustion of CS2 + 3O2 → CO2 + 2SO2 is ... [ KCET 1994]
  • a) - 807 kJ/mol
  • b) -1084 kJ/mol
  • c) +1104 kJ/mol
  • d) +807 kJ/mol
Q.11
When water is added to conc. H2SO4 it gets very hot. This happens because dilution of conc. H2SO4 is .... [ NCERT 1984]
  • a) an exothermic reaction
  • b) an endothermic reaction
  • c) photochemical reaction
  • d) hydrolytic reaction
Q.12
The ΔHfo for CO2(g), CO(g) and H2O(g) are -393.5, -110.5 and -241.8 kJ/mol respectively. The standard enthalpy change ( in kJ) for the reactionCO2(g) + H2(g) → CO(g) + H2O(g) is ... [ IIT 2000]
  • a) 524.1
  • b) 41.2
  • c) -262.5
  • d) -41.2
Q.13
The enthalpy of formation for C2H4(g), CO2(g) and H2O(l) at 25°C and 1atm pressure are 52, -394, -286 kJ/mol respectively. The enthalpy oc combustion of C2H4(g) will be .. [ CBSE PMT 1995]
  • a) + 1412 kJ/mol
  • b) -1412 kJ/mol
  • c) + 141.2 kJ/mol
  • d) -141.2 kJ/mol
Q.14
For which of the following process will energy be absorbed? [ NCERT 1983]
  • a) Separating an electron from an electron
  • b) Separating a proton from proton
  • c) Separating a neutron from neutron
  • d) separating an electron from neutral atom
Q.15
Which one of the following conditions will favour maximum formation of the product in the reaction, ... [NEET 2018] A2 (g) + B2 (g) ⇌ X2 (g) Δr H = – X kJ ?
  • a) High temperature and high pressure
  • b) Low temperature and low pressure
  • c) Low temperature and high pressure
  • d) High temperature and low pressure
Q.16
Which of the following units represents largest amount of energy? [ CPMT 1980]
  • a) Calorie
  • b) Joule
  • c) Erg
  • d) Electron volt
Q.17
The heat of combustion of benzene at 27°C found by bomb calorimeter i.e. for the reactionC6H6(l) + 7.5 O2(g) → 6CO2(g) + 3H2O(l)is 780 kcal/mol. The heat evolved on burning 39g of benzene in an open vessel will be .. [ Manipal PMT 2001]
  • a) 390 kcal
  • b) 780.9 kcal
  • c) 390.45 kcal
  • d) 780 kcal
Q.18
The densities of graphite and diamond at 298K are 2.25 and 3.31 g /cc respectively. If the standard free energy difference (ΔG°) is equal to 1895 J/mol, the pressure at which graphite will be transformed into diamond at 298K is ..
  • a) ;108Pa
  • b) 109Pa
  • c) 1010Pa
  • d) 107Pa
0 h : 0 m : 1 s