What is the sum of the number of neutrons and protons in the heaviest isotope of hydrogen?

Which of the following reactions give $H_2$ as one of the products? (Reactions are not balanced)
$I) NaBH_4 + I_2 \longrightarrow$
$II) B_2H_6 + N(CH_3)_3 \longrightarrow$
$III) Al + NaOH + H_2O \longrightarrow$
$IV) BF_3 + NaH \longrightarrow$

The incorrect statement among the following is:

Describe the bulk preparation of dihydrogen by the electrolytic method. What is the role of an electrolyte in this process?

The radioactive isotope of hydrogen is:

Given below are two statements: one is labelled as Assertion $A$ and the other is labelled as Reason $R$.
Assertion $A$: Physical properties of isotopes of hydrogen are different.
Reason $R$: Mass difference between isotopes of hydrogen is very large.
In the light of the above statements,choose the correct answer from the options given below: