Which of these factors does not govern the stability of a conformation in acyclic compounds?

The pH of a 0.02 M NH₄Cl solution will be :
[given K_b (NH₄OH) = 10^–5 and log 2 = 0.301]

The difference between $$\Delta $$H and $$\Delta $$U ($$\Delta $$H – $$\Delta $$U), when the combustion of one mole of heptane(l) is carried out at a temperature T, is equal to :

1 g of a non-volatile non-electrolyte solute is dissolved in 100 g of two different solvents A and B whose ebullioscopic constants are in the ratio of 1 : 5. The ratio of the elevation in their boiling points, $${{\Delta {T_b}(A)} \over {\Delta {T_b}(B)}}$$, is :