How is $H_2S$ prepared in the laboratory using $FeS$?

Given below are two statements:
Statement $I$ : Nickel is being used as the catalyst for producing syn gas and edible fats.
Statement $II$ : Silicon forms both electron rich and electron deficient hydrides.
In the light of the above statements,choose the most appropriate answer from the options given below:

Which of the following statements is not true for hydrogen:
$1)$ It exists as a diatomic molecule.
$2)$ It has one electron in the outermost shell.
$3)$ It can lose an electron to form a cation which can freely exist.
$4)$ It cannot form ionic compounds.

Which of the following substances will absorb oxygen rapidly?

Explain the isotopes of hydrogen in short.

Arrange the following:
$(i)$ $CaH_2$,$BeH_2$ and $TiH_2$ in order of increasing electrical conductance.
$(ii)$ $LiH$,$NaH$ and $CsH$ in order of increasing ionic character.
$(iii)$ $H-H$,$D-D$ and $F-F$ in order of increasing bond dissociation enthalpy.
$(iv)$ $NaH$,$MgH_2$ and $H_2O$ in order of increasing reducing property.