Which of the following are homogeneous in nature?

(i) ice (ii) wood

(iii) soil (iv) air

On the basis of composition of matter, milk is considered to be:

Which of the following statements are true for pure substances?

(i) pure substances contain only one kind of particles

(ii) pure substances may be compounds or mixtures

(iii) pure substances have the same composition throughout

(iv) pure substances can be exemplified by all elements other than nickel

Two chemical substances X and Y combine together to form a product P which contains both X and Y

X + Y → P

X and Y cannot be broken down into simpler substances by simple chemical reactions. Which of the following statements concerning X, Y and P are correct?

(i) P is a compound

(ii) X and Y are compound

(iii) X and Y are elements

(iv) P has a fixed composition

Which of the following does not have a fixed melting point/boiling point?