The correct statements regarding Boron among the following (1) Nuclear spin of ¹¹B is greater than that of… · ABC26IN0208
Subject: Inorganic Chemistry · Chapter: Main Group Elements · Topic: Main Group Elements – General · Exam: CSIR NET 2019 · Marks: 2 · Difficulty: Easy
The correct statements regarding Boron among the following(1) Nuclear spin of ${}^{11}\mathrm{B}$ is greater than that of ${}^{10}\mathrm{B}$(II) The polarities of B-H bond and C-H bonds are opposite(III) Cross-section of neutron absorption for ${}^{10}\mathrm{B}$ is much more than that of ${}^{11}\mathrm{B}$(IV) B reacts with boiling aq. $\mathrm{NaOH}$ solution to form $\mathrm{NaB(OH)_4}$Are
(a)II and III
(b)I and II
(c)III and IV
(d)II and IV
Answer
Answer: A ✓ checked by 4AB · confidence medium
Answer: II and III.
Explanation
Answer: II and III — ¹¹B has I = 3/2 and ¹⁰B has I = 3, so I is false. B–H is B^δ⁺–H^δ⁻ while C–H is C^δ⁻–H^δ⁺, so II is true. ¹⁰B has a huge thermal-neutron cross-section (~3840 b) compared with ¹¹B, so III is true. Crystalline boron is not attacked by boiling aqueous NaOH (it needs fused alkali), so IV is false.