1 mole of photon, each of frequency 2500 s^-1, would have approximately a total energy of

• 10 erg

• 1 J

• 1 eV

• 1 MeV

2.

The second law of thermodynamic says that in a cyclic process

• work cannot be converted into heat

• heat cannot be converted into work

• work cannot be completely converted into heat

• heat cannot be completely converted into work

The equilibrium constant (K) of a reaction may be written as

• $\mathrm{K} = {\mathrm{e}}^{-∆\mathrm{G}/\mathrm{RT}}$

• $\mathrm{K} ={\mathrm{e}}^{-∆{\mathrm{G}}^{°}/\mathrm{RT}}$

• $\mathrm{K} = {\mathrm{e}}^{-∆\mathrm{H}/\mathrm{RT}}$

• $\mathrm{K} = {\mathrm{e}}^{-∆{\mathrm{H}}^{°}/\mathrm{RT}}$

$\mathrm{For} \mathrm{the} \mathrm{reaction} {\mathrm{SO}}_2 + \frac{1}{2}{\mathrm{O}}_2 \rightleftharpoons {\mathrm{SO}}_3 , \mathrm{if} \mathrm{we} \mathrm{write} {\mathrm{K}}_{\mathrm{p} }= {\mathrm{K}}_{\mathrm{c}}(\mathrm{RT}{)}^{\mathrm{x}}, \mathrm{then} \mathrm{x} \mathrm{become}$

• -1

• $-\frac{1}{2}$

• $\frac{1}{2}$

• 1

Which of the following will decrease the pH of  a 50 mL solution of 0.01 M HCl?

• Addition of 5 mL of 1 M HCl

• Addition of 50 mL of 0.01 M HCl

• Addition of 50 mL of 0.002 M HCl

• Addition of Mg

Equal volumes of molar hydrochloric acid 'and sulphuric acid are neutralized by dilute NaOH solution and x kcal and y kcal of heat are liberated respectively. Which of the following is true ?

• x = y

• x =y/2

• x = 2y

• none of these

Hybridisation of central atom in NF₃ is

• sp³

• sp

• sp²

• dsp²

For the Paschen series the values of n₁ and n₂ in the expression $∆\mathrm{E} =\mathrm{Rhc}\left(\frac{1}{{\mathrm{n}}_1^2}-\frac{1}{{\mathrm{n}}_2^2}\right) \mathrm{are}$

• n₁= 1, n₂ = 2, 3, 4, ...

• n₁= 2, n₂ = 3, 4, 5,...

• n₁= 3, n₂ = 4,5,6,...

• n₁= 4, n₂ = 5,6,7,...

Under which of the following conditions is the relation $∆\mathrm{H} =∆\mathrm{E} + \mathrm{P}∆\mathrm{V}$ valid for a closed system ?

• Constant pressure

• Constant temperature

• Constant temperature and pressure

• Constant temperature, pressure and composition

An organic compound made of C, H and N contains 20% nitrogen. Its molecular weight is

• 70

• 140

• 100

• 65