Answer:
Copper sulphate is an acidic salt: It is the product of the reaction between a weak copper base and a strong acid , H2SO4
Litmus has a red colour in acidic solutions:
Conclusion: Acidic copper sulphate solution turns blue litmus to red
Baking soda is a basic salt : It is the reaction product of a weak acid , CO2 and a strong base , NaOH
Litmus has a blue colour in basic solutions:
Conclusion: basic baking soda solution turns red litmus to blue
