The ratio of mass percentage (w/w) of C : H in a hydrocarbon is 12 : 1. It has two carbon atoms. The weight (in g) of CO₂(g) formed when 3.38 g of this hydrocarbon is completely burnt in oxygen is :

(Given : Molar mass in g mol^–1 C : 12, H : 1, O : 16)

The first and second ionization constants of a weak dibasic acid H₂A are $8.1 \times 10^{-8}$ and $1.0 \times 10^{-13}$ respectively. 0.1 mol of H₂A was dissolved in 1 L of 0.1 M HCl solution. The concentration of HA^- in the resultant solution is:

SF$_4$ is isostructural with :

A. BrF$_4^\ominus$

B. CH$_4$

C. IF$_4^{\oplus}$

D. XeF$_4$

E. XeO$_2$F$_2$

Choose the correct answer from the options given below :

Gas 'A' undergoes change from state 'X' to state 'Y'. In this process, the heat absorbed and work done by the gas is 10 J and 18 J respectively. Now gas is brought back to state 'X' by another process during which 6 J of heat is evolved. In the reverse process of 'Y' to 'X',