In the given reaction $[X]$ will be :

Arrange the acidity of the given four compounds in decreasing order:
$(I)$ $CH_3COCH_2COCH_3$
$(II)$ $CH_3COCH_3$
$(III)$ $CH \equiv CH$
$(IV)$ $CH_3CHO$
Select the correct answer from the codes given below:

The reaction of $CH_3CO_2C_2H_5$ with sodium ethoxide and ethanol gives product $X$. Heating $X$ in the presence of an acid gives $Y$. What is $Y$?

The major products $Q$ and $R$ from the following reactions,respectively are:

Match List-$I$ with List-$II$.
List-$I$:
$(a)$ $\text{Benzene} \xrightarrow[\text{CuCl}]{\text{CO, HCl, Anhyd. AlCl}_3} \text{Benzaldehyde}$
$(b)$ $R-CO-CH_3 + NaOX \rightarrow$
$(c)$ $R-CH_2-OH + R'COOH \xrightarrow{\text{Conc. H}_2\text{SO}_4}$
$(d)$ $R-CH_2COOH \xrightarrow[(ii) H_2O]{(i) X_2/\text{Red P}} R-CH(X)COOH$
List-$II$:
$(i)$ $\text{Hell-Volhard-Zelinsky reaction}$
(ii) $\text{Gattermann-Koch reaction}$
(iii) $\text{Haloform reaction}$
(iv) $\text{Esterification}$
Choose the correct answer from the options given below.

Among formic acid,acetic acid,propanoic acid and phenol,the strongest acid in water is