Question 3 :
The simplest compounds which are made up of two constituents are known as :

Question 4 :
A compound contains atoms of three elements A, B and C. If the oxidation number of A is +2, B is +5 and that of C is -2, the possible formula of the compound is 

Question 12 :
The total number of electrons present in $18$ ml of water (Density of water is $1 \ kg \ L^{-1})$ are ?

Question 15 :
Elements are classified on the basis of similarities in their properties.<br/>

Question 16 :
Which of the following is a property of a pure substance?

Question 17 :
Pure $CuSO_4$ can be obtained from an impure sample by :<br/>

Question 18 :
A liquid is contaminated with non-volatile impunities. Suggest method of purification.

Question 19 :
Which of the following method is used for separation of different components of petroleum ?

Question 26 :
Chromatography is a word that means &#34;color writing&#34;. It is a technique that can be used to separate the components of a mixture.<br/>In this experiment, a marker was used to make a dot a green ink on a piece of paper. The bottom edge of the paper was placed in water, and the water travelled vertically up the paper. As a result, the spot of green ink was separated into two colors: blue and yellow.<br/>Which of the following is the BEST explanation for the fact that the blue ink moved farther up the paper than the yellow ink in this experiment?