Question

Which of the following reacts with water with high rate.

• A. $Li$
• B. $K$
• C. $Na$
• D. $Rb$

Answer 1

Answer: (D)

$Rb$

Answer 2

$2Rb + 2H_{2}O \rightarrow 2RbOH + H_{2}$

$\overset{\quad Li < Na < K < Rb < Cs\quad}{\rightarrow}$

As we go down the group reactivity with $H_{2}O$ increases.