Pick up the wrong statement.

Which of the following processes can be used to obtain heavy water $(D_2O)$?

Which of the following compounds does not contain a peroxide ion?

Two particles $P$ and $Q$ start from the origin and execute Simple Harmonic Motion along the $X$-axis with the same amplitude but with periods $3 \ s$ and $6 \ s$ respectively. The ratio of the velocities of $P$ and $Q$ when they meet is

The correct order of increasing ionic character is:

$A$ meter scale is supported on a wedge at its center of gravity. $A$ body of weight '$w$' is suspended from the $20 \text{ cm}$ mark and another weight of $25 \text{ g}$ is suspended from the $74 \text{ cm}$ mark. The system is balanced and the meter scale remains perfectly horizontal. Neglecting the weight of the meter scale,the weight of the body '$w$' is: (in $\text{ g}$)