Chemistry - Study Mode

[#376] What is the covalency of nitrogen in ammonia molecule
Correct Answer

(B) 3

Explanation

Solution: Covalency is the number of covalent bond of an element or compounds. So nitrogen have 3 covalent bond and 1 co ordinate bond. So covalency of nitrogen is 3.

[#377] What is 'milk of magnesia' chemically?
Correct Answer

(D) Magnesium hydroxide

Explanation

Solution: Magnesium hydroxide is the inorganic compound with the chemical formula Mg(OH)₂. It occurs in nature as the mineral brucite. It is a white solid with low solubility in water. Magnesium hydroxide is a common component of antacids, such as milk of magnesia, as well as laxatives.

[#378] Which one of the following is a micro-element ?
Correct Answer

(A) Chlorine

Explanation

Solution: In analytical chemistry, a trace element or microelement is an element in a sample that has an average concentration of less than 100 parts per million measured in atomic count or less than 100 micrograms per gram. These are those elements essential for plant growth which are needed in only very small (micro). They are: boron (B), copper (Cu), iron (Fe), chloride (Cl), manganese (Mn), molybdenum (Mo) and zinc (Zn).

[#379] Chemical name of bleaching powder is :
Correct Answer

(B) Calcium hypochlorite

Explanation

Solution: Calcium hypochlorite is an inorganic compound with formula CaO(Cl) 2 . It is the main active ingredient of commercial products called bleaching powder, chlorine powder, or chlorinated lime, used for water treatment and as a bleaching agent.

[#380] The chemical formula of the laughing gas is
Correct Answer

(B) N 2 O

Explanation

Solution: Nitrous oxide(N 2 o) is a colourless, sweet-tasting gas. It is also known as "laughing gas".