Explanation

Phenol (C₅H₅OH) has an –OH group capable of strong hydrogen bonding with water.

It forms more hydrogen bonds than ethers or hydrocarbons, leading to higher solubility in water.

Explanation

During electrolysis of fused PbBr₂, Pb²⁺ ions move to the cathode and are reduced to metallic lead.

while Br⁻ ions move to the anode and are oxidized to bromine gas.

Explanation

When ethylene reacts with ozone, it forms ethylene ozonide.

On reduction with Zn-dust and water, the ozonide cleaves to give two molecules of methanal (formaldehyde).

Explanation

25% NaOH solution means 25 g of NaOH in 100 g of solution.

Assume density ≈ 1 g/mL, so 100 g = 100 mL = 0.1 L.

Moles of NaOH = 25/40 = 0.625 mol.

Molarity = 0.625/0.1 = 6.25 M

Explanation

Given:

Mass of sodium = 11.5 g

Atomic mass of sodium (Na) = 23 g/mol

Moles of sodium = 11.5/23 = 0.5 mol

So, the same number of atoms of potassium = 0.5 mol

Mass of potassium = moles × atomic mass = 0.5 × 39 = 19.5 g

Explanation

Transition elements have unpaired d-electrons, which cause them to exhibit paramagnetism.

Some (like Fe, Co, Ni) show ferromagnetism, but generally, most transition elements are paramagnetic.

Explanation

Tincture of iodine is a solution of elemental iodine (I₂) dissolved in alcohol (usually ethanol).

It is commonly used as an antiseptic and disinfectant.

Explanation

1 mole of NO2 contains 32 g of oxygen (since 2 × 16 = 32).

For 16 g of oxygen: 16 ÷ 32 = 0.5 mole of NO2.

Explanation

Mole fraction of water = 0.8

Vapour pressure = 0.8 × 23.8 = 19.04 mm Hg

Hence, the vapour pressure of the solution is 19.04 mm Hg.

Explanation