Explanation

Graphite crystallizes in a hexagonal crystal system with layers of carbon atoms arranged in hexagons.

Substances like diamond belong to the cubic system.

Explanation

Molarity (M) is defined as the number of moles of solute per liter of solution.

It is widely used in chemistry to express solution concentration.

Explanation

DAP (Diammonium Phosphate) is the most widely used phosphorus fertilizer in Pakistan because it supplies both phosphorus (P₂O₅ ~46%) and nitrogen (~18%).

Farmers prefer it due to its high nutrient content and quick availability to crops.

Explanation

pH is calculated as pH = -log[H⁺].

For [H⁺] = 1 × 10⁻⁷ M, pH = 7 → the solution is neutral.

Explanation

Sodium is an alkali metal.

It is very soft.

It can be easily cut with a knife.

Metals like tin and zinc are harder and cannot be cut so easily.

Explanation

John Dalton proposed the Atomic Theory of Matter in 1803.

He stating that all matter is made up of tiny indivisible particles called atoms.

Explanation

Urea (CO(NH₂)₂) is a synthetic nitrogenous fertilizer widely used in agriculture.

It contains about 46% nitrogen.

Explanation

Fragrance spreads because its molecules move from a region of high concentration to low concentration in air.

This natural mixing of particles without external force is called diffusion.

Explanation

NH₄Cl is a salt of a strong acid (HCl) and a weak base (NH₃).

In water, it hydrolyzes to produce H⁺ ions, making the solution acidic.

Explanation

An indicator is a substance that changes color at (or near) the equivalence point of a titration.

It helps to visually determine the end point of the reaction between acid and base (or other reacting solutions).