In the reaction $C_8H_6O_4$ $\xrightarrow{\Delta} X$ $\xrightarrow{NH_3}$,the compound $X$ is

In the reaction sequence:
$CH_3-CH(OH)-COOH$ $\xrightarrow{\Delta } [Y]$
$[Y]$ will be:

Identify product $A$ in the following reaction.
$2 CH_3COOH \xrightarrow{\Delta, P_2O_5} A + H_2O$

The correct order of decreasing acid strength of the following acids is:
$(1)$ Trichloroacetic acid
$(2)$ Trifluoroacetic acid
$(3)$ Acetic acid
$(4)$ Formic acid

Two statements are given below:
Statement $I:$ The melting point of monocarboxylic acids with an even number of carbon atoms is higher than that of acids with an odd number of carbon atoms immediately below and above it in the series.
Statement $II:$ The solubility of monocarboxylic acids in water decreases with an increase in molar mass.
Choose the most appropriate option.

Some pairs of acids are given below. Select the pair in which the second acid is stronger than the first.