When zeolite is treated with hard water,the sodium ions are exchanged with

If $\int e^x(1+x) \cdot \sec ^2(x e^x) \, dx = f(x) + \text{constant}$,then $f(x)$ is equal to

Knowing the properties of $H_{2}O$ and $D_{2}O$,do you think that $D_{2}O$ can be used for drinking purposes?

In which of the following reactions is $H_2O_2$ acting as a reducing agent?

$PbI_4$ does not exist because

$A$ metal rod of length $2 \text{ m}$ has cross-sectional areas $2A$ and $A$ as shown in the figure. The ends are maintained at temperatures $100^{\circ}\text{C}$ and $70^{\circ}\text{C}$. The temperature at the middle point $C$ is...... $^{\circ}\text{C}$