Extraction of gold and silver involves leaching with CN^- ion. Silver is later recovered by:

1. Distillation

2. Zone refining

3. Displacement with Zn

4. Liquation

A 20-litre container at 400 K contains CO₂ (g) at pressure 0.4 atm and an excess of SrO (neglecting the volume of solid SrO). The volume of the container is now decreased by moving the movable piston fitted in the container.
The maximum volume of the container, when the pressure of CO₂ attains its maximum value will be:
(Given that: SrCO₃(s) ⇋ SrO(s) + CO₂(g) , Kp = 1.6 atm) 

The correct statement among the following regarding [Mn(CN)₆]^3-is:

1. It is sp³d² hybridized and tetrahedral.

2. It is d²sp³ hybridized and octahedral.

3. It is dsp² hybridised and square planar.

4. It is sp³d² hybridised and octahedral.

The reason for a greater range of oxidation states in actinoids is attributed to:

1. Actinoid contraction

2. 5f, 6d and 7s levels having comparable energies.

3. 4f and 5d levels being close in energies.

4. The radioactive nature of actinoids

Which of the following statements is not correct?

The ratio of resolving powers of an optical microscope for two wavelengths ${\lambda }_1$=4000 $\stackrel{0}{A}$ and ${\lambda }_2=6000$ $\stackrel{0}{A}$ is:

1. 9:4

2. 3:2

3. 16:81

4. 8:27

The two nearest harmonics of a tube closed at one end and open at the other end are \(220\) Hz and \(260\) Hz. What is the fundamental frequency of the system?

Consider a drop of rainwater having a mass of \(1~\text{gm}\) falling from a height of \(1~\text{km}.\) It hits the ground with a speed of \(50~\text{m/s}.\) Take \(g\)  as constant with a value \(10~\text{m/s}^2.\) The work done by the
(i) gravitational force and the (ii) resistive force of air is:

A physical quantity of the dimensions of length that can be formed out of \(c, G,~\text{and}~\dfrac{e^2}{4\pi\varepsilon_0}\)is:
(\(c\) is the velocity of light, \(G\) is the universal constant of gravitation and \(e\) is charge)