question_answer

  (a) Four students were asked to test the pH of four samples as shown under. Whose result is reported correctly?

Student
A	7	1	1	1
B	7	3	1	1
C	7	1	1	13
D	7	3	1	13

(b) Bottle A contains a dilute solution of vinegar and bottle B contains sodium carbonate solution. Write the colour seen in pH paper dipped in A and B.

Answer:

  (a) The result of student D. It is because, water is neutral having pH = 7  is a weak acid having pH = 3 HCl is a strong acid having pH = 1 NaOH is strong base having pH =13                                                                                                                                          (1) (b) In bottle A colour of pH paper is orange due to the presence of acid (vinegar). In bottle B colour of pH paper is blue due to the presence of base (sodium carbonate solution).