Antiseptic chloroxylenol is

Chloramphenicol is:

Which of the following is a hypnotic?

$A$ chemist has $4$ samples of artificial sweetener $A, B, C$,and $D$. To identify these samples,he performed certain experiments and noted the following observations:
$(i)$ $A$ and $D$ both form blue-violet colour with ninhydrin.
$(ii)$ Lassaigne extract of $C$ gives positive $AgNO_{3}$ test and negative $Fe_{4}[Fe(CN)_{6}]_{3}$ test.
$(iii)$ Lassaigne extract of $B$ and $D$ gives positive sodium nitroprusside test.
Based on these observations,which option is correct?

Given below are two statements: One is labelled as Assertion $A$ and the other labelled as Reason $R$.
Assertion $A:$ Antihistamines do not affect the secretion of acid in stomach.
Reason $R :$ Antiallergic and antacid drugs work on different receptors.
In the light of the above statements,choose the correct answer from the options given below:

Which type of drugs are useful for anxiety and stress?