Percentage of C, H & N in a compound is given as follows:
C=40%; H=13.33%; N=46.67%

The empirical formula of the compound will be:
1. $C{H}_{2}N$
2. $C_2{H}_{4}N$
3. $C{H}_{4}N$
4. $C{H}_{3}N$

An oxide of iron contains 69.9% iron and 30.1% oxygen by mass. What is its empirical formula?

1. FeO

2. Fe₂O₃

3. Fe₃O₄

4. Fe₃O₂

If 2.74 g of the metal oxide contains 1.53 g of metal, then the empirical formula of vanadium oxide is:

(Atomic Mass of V = 52)

1. ${\mathrm{V}}_2{\mathrm{O}}_3$

2. $\mathrm{VO}$

3. ${\mathrm{V}}_2{\mathrm{O}}_5$

4. ${\mathrm{V}}_2{\mathrm{O}}_7$