Assertion (A) Animal skins are colloidal in nature.

Reason (R) Animal skin has positively charged particles.

The diameters range of colloidal particles is approximately.

Which statements among the following are correct?

1. Freundlich isotherm fails at high pressure of the gas.

2. $$\Delta H < 0$$ for both physical and chemical adsorption.

3. Physical adsorption in non-selective.

4. Chemical adsorption is reversible, whereas physical adsorption is irreversible.

In an adsorption experiment, a graph between $$\log (x / m)$$ versus $$\log p$$ was found to be linear with a slope of $$45^{\circ}$$. The intercept on $$\log (x / m)$$ axis was found to be 0.3010. The amount of gas adsorbed per gram of charcoal under a pressure of $$0.5 \mathrm{~atm}$$ is