Explanation

• Wilhelm Conrad Rontgen discovered X-rays
• He was discovered on 8 November 1895.
• He got the Nobel Prize in Physics in 1901.

Additional questions

• The penetrating power of X-rays depends on their frequency

Last updated by NA on 05-11-2026

Explanation

• Copper sulphate pentahydrate contains five molecules of water of crystallization.
• Its crystals are characteristically bright blue due to the presence of hydrated copper(II) ions.
• On heating, it loses its water of crystallization and becomes white anhydrous copper sulphate (CuSO₄).
• Adding water to anhydrous copper sulphate restores its blue color.

Last verified on 02-11-2026

Explanation

• Hydrogenation is an addition reaction in which hydrogen converts benzene into cyclohexane under suitable conditions.
• Benzene commonly undergoes electrophilic substitution reactions in which a hydrogen atom is replaced by an electrophile.
• Halogenation: A hydrogen atom is replaced by chlorine or bromine.
• Nitration: A nitro group (–NO₂) is introduced into the benzene ring.
• Sulphonation: A sulphonic acid group (–SO₃H) is introduced.

Last verified on 02-11-2026

Explanation

• Molecular shape: Long or irregular molecules generally have greater viscosity due to stronger intermolecular interactions and entanglement.
• Temperature: The viscosity of liquids generally decreases when temperature increases.
• Molecular size: Larger molecules often have greater viscosity because of stronger intermolecular forces and greater resistance to flow.
• Therefore, molecular shape, temperature and molecular size all affect the viscosity of liquids.

Last verified on 02-11-2026

Explanation

• Pyroligneous acid is a complex liquid obtained by the destructive distillation of wood in the absence of air.
• Its major components include acetic acid, methanol, acetone and other organic compounds.
• It is also known as wood vinegar.
• Methanol obtained from wood distillation was historically called wood alcohol.

Last verified on 02-11-2026