To purify a sample of crude benzoic acid, activated charcoal can be added to the hot solution to adsorb colored impurities before hot filtration and recrystallisation.

In an investigation, different masses of Charcoal A were added to 100 cm³ samples of hot crude benzoic acid solution. The experiment was repeated with Charcoal B.

The percentages of colored impurities removed are shown in the table below.

Table 1: Effectiveness of Charcoal A and Charcoal B

Mass of charcoal added (g)	Percentage of impurities removed (Charcoal A)	Percentage of impurities removed (Charcoal B)
0.5	28	35
1.0	42	52
1.5	55	68
2.0	70	74
2.5	83	72
3.0	85	64
3.5	78	50

A student concluded:

"The most effective way to purify 100 cm³ of this benzoic acid solution is to add 1.5 g of Charcoal B."

Use the data in Table 1 to evaluate the student's conclusion.

To purify a sample of crude benzoic acid, activated charcoal can be added to the hot solution to adsorb colored impurities before hot filtration and recrystallisation.

In an investigation, different masses of Charcoal A were added to 100 cm³ samples of hot crude benzoic acid solution. The experiment was repeated with Charcoal B.

The percentages of colored impurities removed are shown in the table below.

Table 1: Effectiveness of Charcoal A and Charcoal B

Mass of charcoal added (g)	Percentage of impurities removed (Charcoal A)	Percentage of impurities removed (Charcoal B)
0.5	28	35
1.0	42	52
1.5	55	68
2.0	70	74
2.5	83	72
3.0	85	64
3.5	78	50

A student concluded:

"The most effective way to purify 100 cm³ of this benzoic acid solution is to add 1.5 g of Charcoal B."

Use the data in Table 1 to evaluate the student's conclusion.

3.2 Methods of separating and purifying substances

Question 22

Table 1: Effectiveness of Charcoal A and Charcoal B

Markscheme

3.2 Methods of separating and purifying substances

Question 22

Table 1: Effectiveness of Charcoal A and Charcoal B

Markscheme

3.2 Methods of separating and purifying substances

Question 22

Table 1: Effectiveness of Charcoal A and Charcoal B

3.2 Methods of separating and purifying substances Questions

3.2 Methods of separating and purifying substances

Question 22

Table 1: Effectiveness of Charcoal A and Charcoal B

3.2 Methods of separating and purifying substances Questions