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

What is the product '$X$' in the following reaction?
(Image of $3-$formylcyclohexanone reacting with $[Ag(NH_3)_2]^+$)

Which of the following compounds will most readily be dehydrated to give an alkene under acidic conditions?

The products $C$ and $D$ are given by the following reaction sequence:
$CH_3CH_2COCH_3$ $\xrightarrow[(ii) H_3O^+]{(i) CH_3MgBr} A$ $\xrightarrow[358 \ K]{20\% H_3PO_4} B \text{ (Major)}$ $\xrightarrow[(ii) Zn/H_2O]{(i) O_3} C + D$

The reaction shown below is:
$CH_3CH_2COCH_2CH_3 \xrightarrow{Zn-Hg/HCl} CH_3CH_2CH_2CH_2CH_3$

$C_{7}H_{10}O$ reacts with $CH_{3}MgBr$ to give a compound $C_{8}H_{12}O$ which gives a positive iodoform test. Identify the structure of $A$.