(a) Give two reasons why fused alumina is mixed with cryolite in the electrolytic extraction of aluminium. (b) Write an equation for the reaction of sodium ...
Question 1 Report
(a) Give two reasons why fused alumina is mixed with cryolite in the electrolytic extraction of aluminium.
(b) Write an equation for the reaction of sodium hydroxide with bauxite.
Answer Details
(a) Why fused alumina is mixed with cryolite
- Cryolite dissolves the alumina and lowers its melting point from about 2050 °C to about 950 °C, greatly reducing the energy and cost of the extraction.
- The molten cryolite increases the electrical conductivity of the melt, allowing electrolysis to proceed efficiently.
(b) Reaction of sodium hydroxide with bauxite
The amphoteric alumina in bauxite dissolves in hot concentrated sodium hydroxide to form soluble sodium aluminate: \[Al_2O_{3(s)} + 2NaOH_{(aq)} \rightarrow 2NaAlO_{2(aq)} + H_2O_{(l)}\]
Download The App On Google Playstore
Everything you need to excel in your exams
Personalized AI Learning Chat Assistant
200,000+ Exam Questions Across IGCSE, JAMB, WAEC & NECO
Over 3,900 Lesson Notes
Offline Support - Learn Anytime, Anywhere
Green Bridge Timetable
Literature Summaries & Potential Questions
Track Your Performance & Progress
In-depth Explanations for Comprehensive Learning