Which of the following is not a type of laser?

The reaction of diborane in diethylether with $\underline{X}$ gives metal borohydride. $X$ is a

Which of the following substances does not release $O_2$ and removes water vapor?

Explain the isotopes of hydrogen in short.

Complete the following chemical reactions:
$(i) \ PbS_{(s)} + H_2O_{2_{(aq)}} \to $
$(ii) \ MnO_{4_{(aq)}}^{-} + H_2O_{2_{(aq)}} \to $
$(iii) \ CaO_{(s)} + H_2O_{(g)} \to $
$(iv) \ AlCl_{3_{(g)}} + H_2O_{(l)} \to $
$(v) \ Ca_3N_{2_{(s)}} + H_2O_{(l)} \to $
Classify the above into $(a)$ hydrolysis,$(b)$ redox and $(c)$ hydration reactions.

Formic acid is heated with conc. $H_2SO_4$ at $100^{\circ}C$ to form $A$ and $B$. When $Fe_2O_3$ is heated strongly with $B$,the products formed are $C$ and $D$. $C$ can also be obtained by reacting $CaCO_3$ with dil. $HCl$. What is $D$?