${\mathrm{C}}_2{\mathrm{H}}_4\underset{\text{ (ii) }\mathrm{Zn}/{\mathrm{H}}_2\mathrm{O}}{\overset{\left(\mathrm{i}\right) {\mathrm{O}}_3}{\to }}\mathrm{P}\underset{\text{ (ii) }{\mathrm{H}}_2\mathrm{O}/{\mathrm{H}}^{+}}{\overset{\text{ (i) }{\mathrm{CH}}_3\mathrm{MgBr}/\text{ Ether }}{\to }}\mathrm{Q}\underset{{\mathrm{CH}}_2{\mathrm{CI}}_2}{\overset{\mathrm{PCC}}{\to }}\mathrm{R}$

The incorrect statement about R is 

${\mathrm{C}}_2{\mathrm{H}}_4\underset{\text{ (ii) }\mathrm{Zn}/{\mathrm{H}}_2\mathrm{O}}{\overset{\left(\mathrm{i}\right) {\mathrm{O}}_3}{\to }}2\mathrm{CHO}\underset{\text{ (ii) }{\mathrm{H}}_2\mathrm{O}/{\mathrm{H}}^{+}}{\overset{\text{ (i) }{\mathrm{CH}}_3\mathrm{MgBr}/\text{ Ether }}{\to }}{\mathrm{CH}}_3{\mathrm{CH}}_2\mathrm{OH}\underset{{\mathrm{CH}}_2{\mathrm{CI}}_2}{\overset{\mathrm{PCC}}{\to }}{\mathrm{CH}}_3\mathrm{CHO}$

It has one alpha carbon so it can undergo aldol condensation not cannizaro reaction.