Let 'a' g and 'b 'g be the weights of Al and Zn in the mixture.

a + b = 1.67 … (1)

M_eq of Al + M_eq of Z_n = Meq of H₂

From equations (1) and (2)

a = 1.25 g Al

b = 0.42 g Zn

The orbital with highest value of (n + l) has the highest energy.

For set, 3, 2, 2, 1/2.

Value of n + l is 3 + 2 = 5

It is the highest among given options, hence electron will have the highest energy for this set of quantum numbers.

Second dissociation constant is much smaller than the first one. Just a small fraction of total HCO^-₃ formed will undergo second stage of ionisation. Hence, in saturated solution,

As we move from left to right across a period, ionisation enthalpy increases with increasing atomic number. So, the order of increasing ionisation enthalpy should be B < C < N < O.

But, N (1s² 2s² 2p³) has a stable half filled electron configuration. So, ionisation enthalpy of nitrogen is greater than oxygen. So, the correct order of increasing first ionisation enthalpy is B < C < O < N.

Hence, the order indicated in the option (2) is correct.

The metallic lustre of sodium is due to oscillations of loose electrons. Metals are lustrous because of the free electrons they have. The free electrons can move freely in the metal, causing any light incident on them to get reflected back.

Dilute nitric acid converts chromate into dichromate and H₂O.

2K₂CrO₄ + 2HNO₃ → K₂Cr₂O₇ + 2KNO₃ + H₂O

⇒ 2CrO₄⁻² ⇌ H⁺ + Cr₂O₇²⁻ + H₂O

Acidic medium shifts the equilibrium in the direction of the dichromate ion.

Cyclopentadienyl cation is not aromatic as it contains only 4 pi electrons. So, it does not follow (4n + 2) pi electron rule.

(1) Hydrogenation of an alkene is a heterogeneous process which occurs on the surface of a solid catalyst (PtO₂ or Pd/C). The addition occurs with syn stereochemistry (both hydrogens add from the same side). For cis isomer, the product is a meso compound.

(3) The addition of two hydroxyl groups involves syn addition (on the same side of a double bond). The result is same as that of hydrogenation. The cis isomer produces meso compound.

(4) The addition of two hydroxyl groups involves syn addition (on the same side of a double bond). The result is same as that of hydrogenation. The trans isomer produces racemic mixture.

Schweizer reagent is the chemical complex tetraamminediaquacopper dihydroxide, [Cu(NH₃)₄(H₂O)₂](OH)₂. It is prepared by precipitating copper (II) hydroxide from an aqueous solution of copper sulphate using sodium hydroxide or ammonia, then dissolving the precipitate in a solution of ammonia.