Chemistry Test 77

Cytosine and thymine are pyrimidines which are structures composed of a single six-sided ring. Adenine always binds to thymine, while cytosine and guanine always bind to one another. This relationship is called complementary base pairing.
Hence, the correct option is (C).

Average kinetic energy does not depend on the nature of the gas and their weight. It only depends on temperature. This same temperature condition is given. So, kinetic energies are same.

Then, KE₁ = KE₂

Hence, the correct option is (C).

Neopentane, also called 2,2-dimethylpropane, is a double-branched-chain alkane with five carbon atoms. Neopentane is a flammable gas at room temperature and pressure which can condense into a highly volatile liquid on a cold day, in an ice bath, or when compressed to a higher pressure. Neopentane structure is-

Hence, the correct option is (B).

The sum of coordination number and oxidation number of the metal M in the complex [M(en)₂(C₂O₄)]Cl (where (en) is ethylenediamine) is 9. The coordination number is 6 as en and C₂O₄ are bidentate ligands.

Let X be the oxidation number of M.

X+2(0)−2=+1

X=+3

Thus, the oxidation number is 3.

Hence, the sum of coordination number and oxidation number of the metal M is 6+3=9.
Hence, the correct option is (C).

Calgon is a trading name of a complex salt, sodium hexametaphosphate (NaPO₃)₆.

It is used for softening hard water. Calgon ionizes to give a complex anion: 

(NaPO₃)₆ or Na₂(Na₄P₆O₁₈)? 2Na+ + Na₄P₆O₁₈^2-. 

The addition of Calgon to hard water causes the calcium and magnesium ions of hard water to displace sodium ions from the anion of Calgon

Ca²⁺ + Na₄P₆O₁₈^2-? 2Na+ + CaNa₂ P₆O₁₈^2-.

From hard water anion of calgon goes into solution. This results in the removal of calcium and magnesium ions from hard water in the form of a complex with Calgon. The water is softened and sodium ions are released into the water.

Hence, the correct option is (B).

H₂S is less acidic than H₂Te because as we move down the group, the bond dissociation enthalpy decreases i.e it becomes easy to dissociate or break the bonds.

Ozone is thermodynamically less stable than oxygen because its decomposition into oxygen results in the liberation of heat (is negative) and an increase in entropy (is positive).

Hence, the correct option is (D).

Lead loses its two 6p electrons, but the 6s electrons are left unchanged, an "inert pair". This indicates that it is more difficult to remove the p electrons from lead than from tin.

The inert pair effect is nothing but the extra stability concept. Generally, p-block elements belonging to 3A, 4A, 5A, 6A, etc, show variable valency. For example, the Sn element of group 4A shows a +4 and +2 oxidation state.
Hence, the correct option is (C).

On mixing up the equal volumes of Sodium Hydroxide and Acetic acid at the same concentration, Sodium Acetate is produced.

NaOH + CH₃COOH ⇄ CH₃COONa + H₂O

CH₃COONa, a conjugate base of a weak acid, undergo water hydrolysis with H₂O, producing OH⁻ ion and raising the solution's pH slightly.

Therefore, the yielded solution will be having a basic nature.

Hence, the correct option is (A).

An antacid is a substance that neutralizes stomach acidity and is used to relieve heartburn, indigestion, or an upset stomach. Some antacids have been used in the treatment of constipation and diarrhea. Currently marketed antacids contain salts of aluminum, calcium, magnesium, or sodium.

Sodium carbonate is a chemical compound with the molecular formula Na₂CO₃. It's commonly referred to as washing soda and is used in cleaning products, glass production, as a food additive, and more.
Hence, the correct option is (C).