Which of the following does not give a yellow solid on treatment with sodium hypoiodite?

How will you convert butan-$2$-one to propanoic acid?
$CH_3-CH_2-CO-CH_3 + I_2 + NaOH$ $\rightarrow C_2H_5CO_2^-Na^+ + CHI_3$ $\xrightarrow{H^+} C_2H_5COOH$

Identify the correct statements about $Z$ in the following reaction sequence:
$C_2H_5NH_2$ $\xrightarrow[NaNO_2 / HCl]{} X$ $\xrightarrow{H_2O} Y$ $\xrightarrow{Cu / 573 \ K} Z$
$I$. $Z$ is an aldehyde
$II$. $Z$ undergoes Cannizzaro reaction
$III$. $Z$ gives iodoform test
$IV$. $Z$ does not give test with Tollens' reagent

Which of the following does not give an aldol reaction with dil. $NaOH$?

To obtain $3-$methylbutan$-2-$ol from acetaldehyde,the Grignard's reagent used is

Which one of the following compounds is the best choice for being prepared by an efficient mixed aldol addition reaction?