When formic acid reacts with $PCl_5$,it forms:

An optically active compound $'X'$ having molecular formula $C_4H_8O_3$ evolves $CO_2$ with $NaHCO_3$. $'X'$ on treatment with $LiAlH_4$ gives an achiral compound. Then $'X'$ is

Arrange the following in decreasing order of their acidic strength and give reason for your answer: $CH_{3}CH_{2}OH$,$CH_{3}COOH$,$ClCH_{2}COOH$,$FCH_{2}COOH$,$C_{6}H_{5}CH_{2}COOH$.

What sized ring is formed when two carboxylic acids form a dimeric structure through intermolecular hydrogen bonding? (Consider the hydrogen bond as a bond in the ring structure.)

Which of the following reagents will convert a carboxylic acid into an ester?

Identify $X, Y$ and $Z$ respectively in the following reaction sequence:
$CH_3COOH$ $\xrightarrow[(ii) \Delta]{(i) NH_3} CH_3CONH_2$ $\xrightarrow[Pyridine / 343 \ K]{(iii) C_6H_5SO_2Cl} X + Y + Z$