Explanation

• Main Cause: Freon / CFCs
• Effect: Breaks down O₃ molecules → more UV-B radiation
• Other Contributors: Halons, carbon tetrachloride
• Result: Skin cancer, cataracts, climate impact

• The Montreal Protocol (1987) aimed to reduce CFC emissions
• Ozone layer protects Earth from harmful ultraviolet rays

Explanation

• Battery is a device that converts chemical energy into electrical energy.
• Batteries work by using a galvanic cell.
• It is an electrochemical device made up of two electrodes and an electrolyte solution.

Last verified on 16-03-2026

Explanation

• Electronegativity is the ability of an atom to attract electrons.
• The highest electronegativity value is for fluorine (F), which is 3.98 on the Pauling scale.

Last verified on 07-11-2026

Explanation

• Evaporation is a surface phenomenon that can occur at any temperature.
• It occurs when high-energy molecules escape from the liquid surface into the air.
• Unlike boiling, evaporation does not require the liquid to reach its boiling point.

Last verified on 14-11-2026

Explanation

• SF₄ (Sulfur tetrafluoride) is a molecule of sulfur and fluorine.
• According to VSEPR theory, its shape depends on electron pairs around sulfur.
• Sulfur has 4 bonding pairs + 1 lone pair = 5 electron domains.
• This arrangement gives a see-saw molecular shape.
• Lone pair causes distortion from perfect symmetry.

Last verified on 19-05-2026