MDCAT Chemistry MCQ #5409

When aluminum metal is added to a concentrated solution of sodium hydroxide, it dissolves with the evolution of hydrogen gas. What is the final complex ion formed?

MDCAT Chemistry MCQ #5409

  1. Question 1

    Q1. When aluminum metal is added to a concentrated solution of sodium hydroxide, it dissolves with the evolution of hydrogen gas. What is the final complex ion formed?

    • A) Sodium tetrahydroxoaluminate
    • B) Sodium aluminate (NaAlO2)
    • C) Aluminum hydroxide precipitate
    • D) Sodium aluminum hydride

    Answer: Sodium tetrahydroxoaluminate

    Explanation: Aluminum is amphoteric and reacts with NaOH to form soluble sodium tetrahydroxoaluminate; Al(OH)3 is an intermediate that dissolves in excess base.