Chemistry · Group 13 to Group 18 Elements

Choose the correct answer form the alternatives given. When alkaline earth metal

Choose the correct answer form the alternatives given. When alkaline earth metals dissolve in ammonia, they form coloured solution like alkali metals. Which of the following observations regarding the reaction are correct? (i) Dilute solution are bright blue in colour due to solvated electrons. (ii) These solutions decompose to form amides and hydrogen. (iii) From this solution the ammoniates \( \left[M\left(N H_{3}\right)_{6}\right]^{2+} \) can be recovered by evaporation

  • A. only (i) and (ii)
  • B. Only (i) and (ii) and (iii)
  • C. only (ii) and (iii)
  • D. only (i)

Step-by-step solution

Dilute solutions of alkaline earth metals in ammonia are bright blue due to solvated electrons (i correct). These solutions slowly decompose to form amides and hydrogen gas (ii correct). However, evaporation of the ammonia does not yield the hexaammine complex [M(NH3)6]2+; instead, it typically gives the metal amide, so (iii) is incorrect.
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