The $pH$ of a buffer solution decreases by $0.02$ units when $0.12 \ g$ of acetic acid is added to $250 \ mL$ of a buffer solution of acetic acid and potassium acetate at $27^{\circ} C$. The buffer capacity of the solution is

$A$ gas cylinder can withstand a pressure of $15 \, atm$. The pressure in the cylinder is $12 \, atm$ at $27 \, ^oC$. Up to what temperature in $^oC$ will the cylinder not burst?

The figure shows wave fronts in still water,moving in the direction of the arrow towards the interface $PQ$ between a shallow region and a deep (denser) region. Which of the lines shown may represent one of the wave fronts in the deep region?

Hairs of a shaving brush cling together when it is removed from water due to:

Two identical piano wires have a fundamental frequency of $600 \text{ Hz}$ when kept under the same tension. What fractional increase in the tension of one wire will lead to the occurrence of $6 \text{ beats per second}$ when both wires vibrate simultaneously?

Which of the following is incorrect for physisorption?