Question

Give reasons: 

(a) Neither q nor w is a state function but q + w is state function. 

(b) The dissolution of ammonium chloride in water is endothermic still it dissolves in water. 

Answer 1

q + w = ΔU. As ΔU is a state function, hence q + w is a state function. 

On dissolution, entropy increases i.e., ΔS is +ve. If TΔS > ΔH, 

then ΔG will be –ve. Hence, the process is spontaneous.