Q. Which of the following reacts with water with high rate?
A) Li
B) Rb
C) Na
D) K
Explanation
(b)
$2Rb + 2H_{2}O \rightarrow 2RbOH + H_{2}$
As we go down the group reactivity with $H_{2}O$ increases
$ie,\ \ \overset{\ \ \ Li\ < \ Na\ < \ K\ < \ Rb\ < \ Cs\ \ \ \ \ }{\rightarrow}$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.