Remember, a light or objects looks black, when an object absorbs all the seven colours and reflects none. That time it looks like black in colour.

Bile is dark green or a yellowish-brown fluid which is produced by the liver and comes to the small intestine through hepato-pancreatic duct.

Solution of pH can be made, when Sodium hydroxide (NaOH) that dissolves in water to form a solution. Which has pH as greater than 7. Because it is an alkali.

In Latin, the meaning of “AQUA – REGIA” is Water which is loyal or in another words Loyal water. Aqua – regia can be prepared by mixture of two chemicals, (used by jewellery) first is concentrated HCl and concentrated HNO₃ ...

When manganese dioxide reacts with hydrochloric acid, the manganese dioxide (MnO₂) reduces to MnCl₂ while hydrochloric acid (HCI) oxidizes to chlorine gas (Cl₂).