Which compound does not form iodoform with alkali and iodine?

Splitting of signals in $NMR$ spectroscopy is caused by

$RCH=O + H_2 \xrightarrow{\text{catalyst}} RCH_2OH$. Which catalyst is used for this reaction?

When acetaldehyde is heated with Fehling solution,it gives a red precipitate of:

In the following reaction sequence, the amount of $D$ (in $g$) formed from $10$ moles of acetophenone is. . . . . . (Atomic weights in $g \ mol^{-1}: H = 1, C = 12, N = 14, O = 16, Br = 80$. The yield (%) corresponding to the product in each step is given in the parenthesis)

Acetaldehyde can be converted into $C(CH_2OH)_4$ (pentaerythritol) by which reagent?