Which one of the following is manufactured by the electrolysis of fused sodium chloride?

Which of the following statements is $NOT$ correct?

Fluorosis disease is caused due to the reaction of ...... with excess of fluoride in the body.

$(a)$ Describe the chemical properties of alkali metals with air,water,dihydrogen,and halogens.
$(b)$ Explain the reduction potential of alkali metal elements.
$(c)$ Which type of solutions are formed on the reaction of alkali metals with liquid ammonia?

The element having electronic configuration $[Kr]4d^{10} 4f^{14} 5s^2 5p^6 6s^2$ belongs to

The correct order of increasing ionic character among $LiH$,$NaH$,$KH$,$RbH$,$CsH$ is