Chemical Formula

Q.

Let $X$ and $Y$ be two elements. The formula of a compound made up of $X$ and $Y$ is $X_2{Y}_3$. For a molecule of the compound, the ratio between the Y and X atoms is:

1. X₂Cl

2. XCl₂

3. X₃Cl

4. XCl₃

Q.

Subscripts in the chemical formula $A_3{B}_8$ denote 3 atoms of A are mixed with 8 atoms of B.

1. is true and B is false.

2. A is false and B is true.

Q.

The ratio of hydrogen atoms present in one molecule each of methane and ammonia is:

1. AlO₂

2. Al₂O₃

3. Al₃O₂

4. AlO

Q. State two examples in each case and write their chemical formulae: (3 marks)
(i) Molecules having one kind of atoms only.
(ii) Molecules having two different kinds of atoms.
(iii) Molecules having three different kinds of atoms.

Q.

The correct representation of the chemical formula of common salt is

1. nacl

2. NaCl

3. NACL

4. NaCL

Q.

The total number of atoms in $2C_6{H}_{12}{O}_6$ is:

1. is true and B is false.

2. A is false and B is true.

3. Both A and B are true

4. Both A and B are false

Q. Chemical formula of a compound is determined on the basis of __________ of its constituents.

1. number of neutrons
2. valency
3. atomic mass
4. atomic size

Q. The camber provided on a sloping road is 1 in 48. Which one of the following is the ruling gradient?

1. 1 in 20
2. 1 in 15
3. 1 in 30
4. 1 in 24