WAEC Chemistry 2025 Theory — Question 29
Question 29 of 70 from the West African Examinations Council (WAEC) Chemistry 2025 Theory paper, with the correct answer and a full explanation.
Advertisement
2(e)(ii). Explain the effect of concentration on the anion that is preferentially discharged in the electrolysis of brine.
Model answer
Brine is a concentrated aqueous solution of sodium chloride (NaCl). The anions competing for discharge at the anode are Cl- and OH-. OH- is lower in the electrochemical series (more easily discharged based on position alone), but Cl- is preferentially discharged instead because of its much higher concentration in brine.
Advertisement
Sign up free to unlock
- Score tracking
- Practice history
- Saved questions
- Progress dashboard
- Personalized sessions
- Weak-topic breakdown
…and/or go further with premium services and No Ads.