If $A$ and $B$ are any two sets,then $(A \cup B)'$ is equal to

Consider the following bromides:
The correct order of $S_N1$ reactivity is

Pressure versus temperature graphs of an ideal gas are as shown in the figure. Choose the wrong statement.

Excess of which of the following in water causes blue baby syndrome disease?

Which of the following is not a class of $Bryophytes$?

The line $x=\frac{\pi}{4}$ divides the area of the region bounded by $y=\sin x$,$y=\cos x$ and the $x$-axis $(0 \leq x \leq \frac{\pi}{2})$ into two regions of areas $A_1$ and $A_2$. Then $A_1 : A_2$ equals (in $: 1$)