Which of the following contains a coordinate covalent bond?
A. Cl₂
B. NH₄⁺
C. NH₃
D. NaCl
Answer: Option B
Solution (By JKExamLibrary)
Ammonium ion (NH₄⁺) contains a coordinate bond: NH₃ donates its lone pair of electrons to H⁺ to form a covalent bond where both electrons come from nitrogen. NaCl is ionic, NH₃ has ordinary covalent bonds, Cl₂ has a nonpolar covalent bond. In NH₄⁺, all four N–H bonds are equivalent after formation. Coordinate bond is also called dative bond and is common in complex ions like [Cu(NH₃)₄]²⁺.
Explanation:
Natural rubber (cis-1,4-polyisoprene) is an addition polymer of isoprene (2-methyl-1,3-butadiene). It is obtained from latex of rubber tree (Hevea brasiliensis). It is elastic but weak. Vulcanization with sulfur introduces cross-links, improving strength and elasticity. Ethene gives polyethylene; styrene gives polystyrene; vinyl chloride gives PVC.
Explanation:
Half-life is a characteristic of first-order kinetics, and all radioactive decay follows first-order kinetics. Hence it applies to all radioactive decay processes. Chemical reactions of first order also have constant half-life independent of initial concentration, but radioactive decay is the prime example. Zero-order half-life depends on initial concentration.
Assertion (A): The Montreal Protocol was signed to control the emission of CFCs. Reason (R): CFCs are responsible for the depletion of the ozone layer.
A.A is true but R is false.
B.A is false but R is true.
C.Both A and R are true but R is NOT the correct explanation of A.
D.Both A and R are true and R is the correct explanation of A.
Explanation:
The Montreal Protocol is an international treaty designed to protect the ozone layer by phasing out the production of numerous substances responsible for ozone depletion, most notably chlorofluorocarbons (CFCs). Both statements are correct, and R perfectly explains the purpose of the protocol.
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