question_answer 39)

  Alkali metals react with water vigorously to form hydroxides and dihydrogen. Which of the following alkali metals reacts with water least vigorously? (a) Li                     (b) Na                                   (c) K                      (d) Cs

Answer:

  (a) Lithium is least reactive amongst alkali metals and it reacts with water least vigorously as it has the highest ionisation enthalpy amongst alkali metals.