Molar mass of the hydrocarbon $(X)$ which on ozonolysis consumes one mole of $O_3$ per mole of $(X)$ and gives one mole each of ethanal and propanone is $...... g\ mol^{-1}$ (Molar mass of $C: 12\ g\ mol^{-1}, H: 1\ g\ mol^{-1}$)

Given below are two statements: one is labelled as Assertion $A$ and the other is labelled as Reason $R.$
Assertion $A :$ Treatment of bromine water with propene yields $1-$bromopropan$-2-$ol.
Reason $R:$ Attack of water on bromonium ion follows Markovnikov rule and results in $1-$bromopropan$-2-$ol.
In the light of the above statements,choose the most appropriate answer from the options given below:

The major product $(P)$ formed in the below reaction is:
$CH_2$ attached to a cyclohexane ring $\xrightarrow[(ii) NaBH_4, OH^-]{(i) Hg(OAc)_2, H_2O-THF} P?$

What is the product of the reaction $CH_3CH_2CH=CH_2$ $\xrightarrow{1. Hg(OAc)_2, H_2O}$ $\xrightarrow{2. NaBD_4}$?

What is the correct order of stability for the following alkenes?

In hydroboration reaction:
$I$. $Syn$ addition takes place
$II$. Reaction proceeds through formation of a cyclic transition state
$III$. Markovnikov rule is followed in the reaction
$IV$. Anti-addition takes place and anti-Markovnikov rule is followed
Which statement$(s)$ is/are correct?