The major product of the following reaction is:

Oxalic acid reacts with concentrated $H_2SO_4$ to give a mixture of two gases. When this mixture is passed through caustic potash,one of the gases is absorbed. What is the product formed by the absorbed gas with caustic potash?

When $C_6H_5Z$ undergoes electrophilic substitution,the major product obtained is the meta-isomer. Therefore,the group $Z$ is:

Dimerisation in carboxylic acid is due to

The reaction is fastest when $X$ is
$R-C(=O)-X + Nu^- \rightarrow R-C(=O)-Nu + X^-$

$C_6H_5CH_2MgBr$ $\xrightarrow[\text{(ii) } H_3O^{+}]{\text{(i) } CO_2 / \text{Ether}} \text{'X'}$ $\xrightarrow[\Delta]{NaOH + CaO} \text{'Y'}$
What is the final product in this reaction?