WAEC 2021 - CHEMISTRY PRACTICAL ANSWER
VERY IMPORTANT INFORMATION!!!
PLEASE REMEMBER TO USE YOUR SCHOOL'S AVERAGE TITRE VALUE(AVERAGE VOLUME OF ACID). WE USED 24.32cm³, TRY TO KNOW YOUR SCHOOL'S AVERAGE TITRE VALUE. ASK YOUR CHEMISTRY TEACHER. THEN, ANYWHERE YOU SEE 24.32cm³ IN MY CALCULATION, PUT YOUR SCHOOL'S OWN AND RE-CALCULATE. THIS IS VERY IMPORTANT!!!
MAKE SURE YOU ADD WHEN YOU SUBTRACT YOUR FINAL BURETTE READING FROM INITIAL BURETTE READING, IT WILL GIVE YOU YOUR SCHOOL'S AVERAGE TITRE VALUE.
ANYWHERE U SEE ME USE 24.32, REMOVE IT AND USE UR SCHOOL FIGURE WHICH U GOT IN UR TABLE.
The value will increase
The occur as a result of the decrease in the concentration of base due to the added volume of water
There will be no visible reaction because copper is less than Zinc in the electrochemical series
It absorb water and become sticky because it is hygroscopic
The solution turns pink
When NaOH is added to the solution of zn³+, a white precipitate is formed which later dissolve in excess NaOH due to the formation of zinc hydroxide