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

In the following sequence of reactions,compound $M$ is:
$M$ $\xrightarrow{CH_3MgBr} N + CH_4 \uparrow$ $\xrightarrow{H^+} CH_3COCH_2COCH_3$

Which of the following reactions converts the carbonyl group of aldehydes and ketones to a methylene group on treatment with zinc amalgam and concentrated $HCl$?

Ethane can be obtained from ethanal in one step by

The product of reduction of benzaldehyde is

For the conversion of cyclohexanone to $1-$hydroxy$-1-$methylcyclohexan$-2-$one,the correct order of reagents used is:
$(1)$ $CH_3MgBr / H^+$
$(2)$ $H^+ / \Delta$
$(3)$ $KMnO_4$ (cold dil.)
$(4)$ $CrO_3$