Question

If 60 ml of water contains 12% of chlorine, how much water must be added in order to create a 8% chlorine solution? (a) 10ml (b) 35ml (c) 20ml (d) 30ml

Answer 1

Answer:

c) 20ml of water should be added

Answer 2

ᴄᴏʀʀᴇᴄᴛ ᴀɴsᴡᴇʀ:

• d. 30ml

ɢɪᴠᴇɴ :

• total quantity of water is 60 ml
• contains 12% of chlorine

ᴛᴏ ғɪɴᴅ:

• the quantity of water must be added in order to create a 8% chlorine

sᴏʟᴜᴛɪᴏɴ :

Let x ml of chlorine be present in water.

Then, $\sf{\frac{12}{100} = \frac{x}{60}}$

→ x = $\sf{\frac{12}{100} × 60}$

→ x = 7.2 ml

Therefore, 7.2 ml is present in 60 ml of water.

In order for this 7.2 ml to constitute 8% of the solution, we need to add extra water. Let this be y ml.

Then, $\sf{\frac{8}{100} = \frac{7.2}{y}}$

→ y = 90 ml.

So in order to get a 8% chlorine solution, we need to add 90 - 60 = 30 ml of water.