Which among the following salts turns red litmus blue in its aqueous solution?

Identify ' $B$ ' in the following sequence of reactions.

Acetic acid $\xrightarrow[\Delta]{\text { Thionyl chloride }} \mathrm{A} \xrightarrow{\text { Ammonia }} \mathrm{B}$

A container consists mixture of four gases as $5 \mathrm{~g} \mathrm{H}_2, 8 \mathrm{~g} \mathrm{He}, 50 \mathrm{~g} \mathrm{CO}_2$ and 20 g Ne at a certain temperature. Which of the following gases exerts minimum partial pressure?

Calculate the work done if 1 mole of certain gas compressed isothermally and reversibly at 300 K from initial pressure $x$ bar to final pressure $2 x$ bar $\left[\mathrm{R}=8.314 \mathrm{~J} \mathrm{~K}^{-1} \mathrm{~mol}^{-1}\right]$