Explanation

Carboxy methyl cellulose (CMC) helps keep dirt suspended in water after it is removed from clothes, preventing it from re-depositing.

If washing powder lacks CMC, dirt may settle back onto the fabric during washing.

Explanation

Petrol typically contains around 0.05% sulfur, which can contribute to air pollution when burned.

The sulfur content in fuels is regulated to reduce harmful emissions and environmental impact.

Explanation

Mercury (Hg) is used in thermometers.

Because it expands and contracts consistently with temperature changes.

It providing accurate readings.

It also emits ultraviolet light in fluorescent tubes when electrically excited.

Explanation

Iron rusts when it reacts with oxygen and water in the air, forming iron hydroxide (Fe(OH)₃).

This compound eventually dehydrates to form iron oxide, the reddish-brown rust.

Explanation

Hydrogen bonding occurs when hydrogen is bonded to highly electronegative atoms like fluorine, oxygen, or nitrogen.

HCl does not form hydrogen bonds because chlorine is not electronegative enough to form such interactions with hydrogen.

Explanation

Ammonia (NH₃) has a trigonal pyramidal shape due to one lone pair on the nitrogen atom.

The molecular geometry results from sp³ hybridization and lone pair-bond pair repulsion.

Explanation

Explanation

Temperature increases kinetic energy, speeding up diffusion.

Intermolecular forces affect how easily gas particles move past each other.

Molecular mass affects rate inversely — lighter gases diffuse faster (Graham's Law).

Explanation

Sodium is a reducing agent because it loses electrons easily.

Oxidizing agents gain electrons; chlorine, nitric acid, and nitrogen can act as oxidizers, but sodium cannot.

Explanation

Dental amalgam is a mixture of liquid mercury in solid metal alloys like silver, tin, and copper.

It forms a solid solution once set, where the liquid (mercury) is dispersed in the solid.