A chemical compound always contains the same elements combined together in the same proportion or ratio. This is the statement of the ?

D. Law of Reciprocal Proportions

Which is not true about benzene?

C. 6 sites for monosubstitution

A. It has a planar hexagonal ring structure

B. It has delocalized pi electrons

C. 6 sites for monosubstitution

D. Its molecular formula is C₆H₆

Everyday Science · Atoms, Elements & Compounds · page 16 of 20

Compounds MCQs with Answers

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Compounds MCQs (151–160)

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151.
The main intermolecular force in NH₃ is?
Correct Answer: D. Hydrogen bonding
One-liner
The main intermolecular force in NH₃ (ammonia) is hydrogen bonding.
152.
A chemical compound always contains the same elements combined together in the same proportion or ratio. This is the statement of the ?
Correct Answer: B. Law of Definite Proportions
One-liner
The statement refers to the Law of Definite Proportions (also called the Law of Constant Composition), which states that a chemical compound always contains the same elements combined in a fixed ratio by mass.
153.
Which one of the following compounds is aromatic?
Correct Answer: A. Benzene
One-liner
Benzene is an aromatic compound because it has a planar ring structure with delocalized pi electrons following Hückel's rule (4n+2 π electrons).
154.
The number and types of bonds between two carbon atoms in CaC₂ are ?
Correct Answer: C. One sigma and two pi bonds
One-liner
In calcium carbide (CaC₂), the two carbon atoms are joined by one sigma and two pi bonds, forming a triple bond.
155.
Lactose is ?
Correct Answer: A. Milk sugar
One-liner
Lactose is milk sugar, a disaccharide found naturally in the milk of mammals.
156.
All of the following are organic compounds except _?
Correct Answer: C. Water
One-liner
All of the following are organic compounds except Water, which is an inorganic compound.
157.
The symbolic representation of molecule of a compound is called?
Correct Answer: D. Formula
One-liner
The symbolic representation of a molecule of a compound is called its Formula.
158.
Which element is common to all bases?
Correct Answer: D. Oxygen
One-liner
Oxygen is the element common to all bases, as bases contain the hydroxide (OH⁻) ion or oxide (O²⁻) ion.
159.
The weight of 1.12 Litres of CO₂ at Standard Temperature and Pressure (S.T.P) would be _?
Correct Answer: C. 2.2 g
One-liner
The weight of 1.12 L of CO₂ at STP is 2.2 g.
160.
Which is not true about benzene?
Correct Answer: C. 6 sites for monosubstitution
One-liner
Benzene has only 1 site for monosubstitution because all six hydrogen positions are equivalent due to its symmetrical ring structure.

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Compounds MCQs with Answers

Compounds MCQs (151–160)

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