$CH_3-CH_2-CHO \xrightarrow{Red\,P + HI} A$. Product $A$ is:

Which of the following compounds will undergo self-aldol condensation in the presence of cold dilute alkali?

Write down functional isomers of a carbonyl compound with molecular formula $C_3H_6O$. Which isomer will react faster with $HCN$ and why? Explain the mechanism of the reaction also. Will the reaction lead to the completion with the conversion of whole reactant into product at reaction conditions? If a strong acid is added to the reaction mixture what will be the effect on concentration of the product and why?

The final product of the following reaction is/are:

The increasing order of the rate of $HCN$ addition to the following compounds is:
$(A)\ HCHO$
$(B)\ CH_3COCH_3$
$(C)\ PhCOCH_3$
$(D)\ PhCOPh$

Which statement about the aldol condensation is correct?