Explanation

Aqua regia (a mixture of HCl and HNO₃) is strong enough to dissolve gold, platinum, and palladium.

Silver and iridium do not dissolve in aqua regia easily.

Explanation

A neutral solution (pH 7) does not affect litmus paper, so both red and blue litmus remain unchanged.

Litmus paper changes color only in acidic (red) or basic (blue) solutions.

Explanation

When an acid reacts with a carbonate, it produces salt, water, and carbon dioxide as products.

A general reaction is:

Acid + Carbonate → Salt + Water + CO₂

Example: HCl + CaCO₃ → CaCl₂ + H₂O + CO₂

Explanation

According to the law of conservation of mass, the total mass of reactants equals the total mass of products in a chemical reaction.

Since no atoms are lost or gained, the mass of Fe₂O₃ (product) remains 320 grams, the same as the reactants.

Explanation

6CO₂ + 6H₂O → C₆H₁₂O₆ + 7O₂

The given reaction is the photosynthesis equation, where carbon dioxide and water form glucose and oxygen.

To balance oxygen atoms, the reaction requires 6 oxygen molecules (O₂), which contain 12 oxygen atoms on both sides.

Explanation

Diamond is a non-metal with a high-density.

Graphite: A non-metal but has a lower density (~2.2 g/cm³).

Hydrogen: The lightest element with very low density (~0.000089 g/cm³).

Helium: Also very low density (~0.00018 g/cm³).

Diamond: A non-metal form of carbon with high density (~3.5 g/cm³).

Iron: A metal, so not a valid choice for a non-metal category.

Explanation

Metals are opaque, meaning they do not allow light to pass through.

They are malleable (can be hammered into thin sheets) and lustrous (shiny in appearance).

Explanation

Herbicides also known as Weedkillers.

It is used to control undesired plants.

Explanation

The K orbit, also known as the first electron shell.

• It can hold a maximum of 2 electrons.

The L orbit, also known as the second electron shell.

• It can hold a maximum of 8 electrons.

The M orbit, also known as the third electron shell.

• It can hold a maximum of 18 electrons.

Explanation

Mass number = Protons + Neutrons

Given 6 protons and 6 neutrons, the mass number is 6 + 6 = 12.