Aldehydes, Ketones and Carboxylic Acids

The major product (P) in the following reaction is :

Complex $A$ has a composition of ${\mathrm{H}}_{12}{\mathrm{O}}_6{\mathrm{C}\mathrm{l}}_3\mathrm{C}\mathrm{r}$ . If the complex on treatment with conc.   ${\mathrm{H}}_2{\mathrm{S}\mathrm{O}}_4$ loses  $13.5\mathrm{\%}$ of its original mass, the correct molecular formula of   $\mathrm{A}$ is:

[Given : atomic mass of $\mathrm{C}\mathrm{r}=52\mathrm{a}\mathrm{m}\mathrm{u}$ $\mathrm{A}$ and   $\mathrm{C}\mathrm{l}=35\mathrm{a}\mathrm{m}\mathrm{u}$ ]

The major product in the following reaction is:

Which compound would give 3-methyl-6-oxoheptanal upon ozonolysis?

An organic compound [A], molecular formula C?H?O?, was hydrolyzed with dilute sulphuric acid to give a carboxylic acid [B] and an alcohol [C]. Oxidation of [C] with CrO? – H?SO? produced [B]. Which of the following structures are not possible for [A]?