The haloform test is given by which of the following substances?

Which of the following compounds will not undergo the Cannizzaro reaction when treated with $50\%$ aqueous alkali?

Complete reaction of acetaldehyde with excess formaldehyde,upon heating with conc. $NaOH$ solution,gives $P$ and $Q$. Compound $P$ does not give Tollens' test,whereas $Q$ on acidification gives positive Tollens' test. Treatment of $P$ with excess cyclohexanone in the presence of catalytic amount of $p$-toluenesulfonic acid $(PTSA)$ gives product $R$. Sum of the number of methylene groups $(-CH_2-)$ and oxygen atoms in $R$ is....

Identify the test from the following in which an aldehyde,when boiled with an ammoniacal silver nitrate solution,deposits silver.

$x$ is the product obtained from propanenitrile and stannous chloride in the presence of hydrochloric acid followed by hydrolysis. $y$ is the product obtained from but$-2-$ene by ozonolysis followed by hydrolysis. From the following, which product is not obtained when one mole of $x$ and one mole of $y$ react with each other in the presence of alkali followed by heating?

Arrange the following compounds in increasing order of their reactivity in nucleophilic addition reaction :
$(P)$ Benzaldehyde
$(Q)$ $p-$Tolualdehyde
$(R)$ $p-$Nitrobenzaldehyde
$(S)$ Acetophenone