Menstrual flow occurs due to lack of

$A$ weak acid $HX$ has the dissociation constant $1 \times 10^{-5} \ M$. It forms a salt $NaX$ on reaction with alkali. The percentage hydrolysis of $0.1 \ M$ solution of $NaX$ is ........ $\%$.

Which of the following glands is responsible for immunity in humans?

For a gas,$\frac{R}{C_{v}}=0.4$,where $R$ is the universal gas constant and $C_{v}$ is the molar specific heat at constant volume. The gas is made up of molecules which are

Match List-$I$ with List-$II$ and then select the correct answer from the codes given below the lists:

List-$I$	List-$II$
$A$. Butane $\to$ Isobutane	$a$. Cracking
$B$. Butane $\to$ Lower hydrocarbons	$b$. Isomerisation
$C$. $n$-Heptane $\to$ Toluene	$c$. Reed reaction
$D$. Propane $\to$ $CH_3CH_2CH_2SO_2Cl$	$d$. Aromatisation

The yellow colour solution of $Na_2CrO_4$ changes to orange-red on passing $CO_2$ gas due to the formation of