Question

Which of the following can be used as a filter?
A.Oil paper
B.Silicon dioxide
C.Unglazed porcelain
D.Plastic

Answer 1

Hint: In order to use a substance as a filter for water, the substance should be pocket – friendly and it should have small pores which can filter out the impurities in water.

Complete step by step answer:
Now, we will consider each option one by one.
Option A – Oil paper. It is a paper which is made waterproof by soaking in oil. So, water does not stay on the paper. In order to filter out impurities, the substance should be such that water passes through it. Therefore, oil paper can not be used for filtering water as it does not fulfil the basic criteria of an efficient filter.
Option B – Silicon dioxide. It is a compound used as an anti – caking agent. It is used to prevent formation of lumps in substances like salt. In order for a substance to be suitable for water filtering, it should be a solid which has pores. On the contrary, silicon dioxide is a powder. Hence, it is not suitable for use in water filters.
Option C – Unglazed porcelain. It is porous in nature. Unglazed porcelain can be used to filter water as it is available at affordable prices and is a quite effective filtering substance. It has fine pores which can trap dust and other impurities from water.
Option D – Plastic. It is completely non – porous in nature. Plastic can not be used as a filter because of its non – porous nature.

Therefore, the correct answer is option C.
Additional information: In order to qualify as a filter, a substance should fulfil the following criteria –
-It should be cost effective
-It should be able to remove the impurities from water
-It should have fine pores in order to filter out dirt and other impurities.

Note:
When the purpose of filters is to clean and purify water, the substance to be used for this purpose should be such that it does complete justice to the purpose.