In the following reaction sequence, compound J ($\text{C}_9\text{H}_8\text{O}_2$) is an intermediate. J gives effervescence on treatment with $\text{NaHCO}_3$ and a positive Baeyer's test.

$\text{I} \xrightarrow{(\text{CH}_3\text{CO})_2\text{O},\; \text{CH}_3\text{COONa}} \text{J} \xrightarrow{(i)\ \text{H}_2,\; \text{Pd/C}\; (ii)\ \text{SOCl}_2\; (iii)\ \text{anhyd.}\; \text{AlCl}_3} \text{K}$

The compound I is: