Bond dissociation energy of CH4 is 360 kJ/mol and C2H6 is 620 kJ/mol. Then bond dissociation energy of C-C bond is
170 kJ/mol
50 kJ/mol
80 kJ/mol
220 kJ/mol
C.
80 kJ/mol
Dissociation energy of methane = 360 kJ mol-1
Bond energy of C-H bond =
Bond energy of ethane,
1(C-C) 6 (C-H) =620 kJ/mol
(C-C) + 6 90 = 620
(C-C) + 540 = 62
C-C = 80 kJ mo1-1
Bond dissociation of C-C bond= 80 kJ moJ-1.
In Bohr's Orbit, indicates
Momentum
Kinetic energy
Potential energy
Angular momentum
D.
Angular momentum
Angular momentum =
Arrange the following gases in order of their critical temperature.
NH3, H2O, CO2, O2
NH3 > H2O > CO2 > O2
O2 > CO2 > H2O > NH3
H2O > NH3 > CO2 > O2
CO2 >O2 >H2O > NH3
C.
H2O > NH3 > CO2 > O2
Greater are the intermolecular forces of attraction, higher is the critical temperature.
At equilibrium which is correct?
G = 0
S = 0
H = 0
= 0
A.
G = 0
In unfavorable reaction have Delta G values that are positive (also called endergonic reaction). When Delta G for reaction is zero, a reaction is said to be at equilibrium. Equilibrium does not mean equal concentrations. If the Delt G is zero, there is no net change in A and B, as the system is at equilibrium.
Threshold frequency of a metal is 5 1013 s-1 upon which 1 x 1014s-1 frequency light is focused. Then the maximum kinetic energy of emitted electron is
3.3 10-21
3.3 10-20
6.6 10-23
6.6 10-20
B.
3.3 10-20
Following the conservation of energy principle,
Kinetic energy = h(-)
=(6.626 10-34) (1014s-1 - 5 1013 s-1)
=(6.626 x 10-34J s) (5 x 1013 s-1)
=3.313 x 10-20J.
pKa increases in benzoic acid when substituent "x" is bonded at para-position, then "x" is
-COOH
-NO2
-CN
-OCH3
D.
-OCH3
Larger the value of pKa smaller will be its acidity. Out of the four groups, -COOH, -NO2 and -CN are e- withdrawing which makes benzoic acid more acidic whereas -OCH3 is e- donating which reduces the acidity (makes H less easily available). pKa value increases if OCH3 is present at para-position of benzoic acid.
Which has the highest pH?
CH3COOK
Na2CO3
NH4Cl
NaNO3
B.
Na2CO3
NH4Cl solution is acidic, its pH < 7. NaNO3 solution is neutral, its pH = 7. CH3COOK and Na2CO4solutions are basic their pH > 7. But Na2CO3 solution is more basic, its pH > pH of CH3COOK solution.
At 60° and 1 atm, N2O4 is 50% dissociated into NO2 then KP is
1.33 atm
2 atm
2.67 atm
3 atm
B.
2 atm
Initially 1 0
At equili. 1- 2
N2O4 is 50% dissociated, so =