The compound containing a coordinate covalent bond is:
A. CH₄
B. NH₄⁺
C. NaCl
D. H₂O
Answer: Option B
Solution (By JKExamLibrary)
Ammonium ion (NH₄⁺) is formed when NH₃ donates its lone pair to H⁺, forming a coordinate (dative) bond. CH₄ and H₂O have ordinary covalent bonds; NaCl is ionic. In NH₄⁺, all four N–H bonds become equivalent.
Explanation:
Iodine-131 is a radioactive isotope used to treat thyroid disorders including goitre and cancer. Carbon-14 for dating, Cobalt-60 for cancer therapy, Uranium-235 as fuel in nuclear reactors. Non-radioactive isotopes are used as tracers. Goitre is often caused by iodine deficiency, but radioactive iodine can be used therapeutically.
Assertion (A): HF has an unusually high boiling point. Reason (R): Fluorine is the most electronegative element, leading to strong hydrogen bonding in HF.
A.A is false but R is true.
B.A is true but R is false.
C.Both A and R are true and R is the correct explanation of A.
D.Both A and R are true but R is NOT the correct explanation of A.
Explanation:
HF exhibits strong intermolecular hydrogen bonding because fluorine is highly electronegative and small in size. This strong hydrogen bonding requires significantly more thermal energy to break compared to other hydrogen halides, giving HF an unusually high boiling point. Both statements are true and R correctly explains A.
Consider the following statements: 1. A buffer solution resists changes in pH upon adding small amounts of acid or base. 2. A buffer is made of a strong acid and its conjugate base. Which is/are correct?
Explanation:
A buffer solution maintains a relatively constant pH when small amounts of strong acid or base are added. However, it is typically composed of a weak acid and its conjugate base (or a weak base and its conjugate acid). A strong acid completely dissociates and cannot form a buffer system. Thus, only statement 1 is correct.
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