NEET Practice Questions (MCQs) with Answers & Solutions

One mole of a non-ideal gas undergoes a change of state (2.0 atm, 3.0 L, 95 K)$\to$(4.0 atm, 5.0 L, 245 K) with a change in internal energy, $∆$U = 30.0 L atm. The change in enthalpy ($∆$H) of the process in L atm is:

At absolute zero, the entropy of a perfect crystal is zero. This is........... of thermodynamics.

At constant pressure and temperature, the direction of any chemical reaction is one where, the...... decrease.

The work done by a mass less piston in causing an expansion $∆$V (at constant temperature), when the opposing pressure, P is variable, is given by:

Entropy decreases during:

What is the entropy change for the reaction given below, 

2H₂ (g) + O₂ (g) $\to$2H₂O(l)

at temperature 300 K? Standard entropies of H₂ (g), O₂(g) and H₂O(l) are 126.6, 201.20 and 68.0 JK^-1mol^-1 respectively.

If S$°$ for H₂, Cl₂ and HCl are 0.13, 0.22 and 0.19 kJ K^-1mol^-1 respectively. The total change in standard entropy for the reaction, H₂ + Cl₂ $\to$2HCl is:

In a flask, colourless N₂O₄(g) is in equilibrium with brown coloured NO₂(g). At equilibrium when the flask is heated to 100$°$C, the brown colour deepens and on cooling it becomes coloured. Which statement is incorrect about this observation?

Enthalpy of the reaction,

 CH₄(g) + 1/2 O₂(g) $\to$CH₃OH (l), is negative. If enthalpy of combustion of CH₄ and CH₃OH are x and y respectively, then which relation is correct?                                 

In the reaction, $∆$H and $∆$S both are positive. In which of the following cases, the reaction would not be spontaneous?