5.74 g of a substance occupies 1.2 cm³. Express its density keeping significant figures in view.

The correct option is 4.8 g cm^-3.

To find the density of the substance, we use the standard formula for density:
$$\text{Density}=\frac{\text{Mass}}{\text{Volume}}$$

From the given data:
Mass of the substance = 5.74 g (which has 3 significant figures)
Volume occupied = 1.2 cm³ (which has 2 significant figures)

Substituting these values into the density formula:
$$\text{Density}=\frac{5.74\text{g}}{1.2{\text{cm}}^3}\approx \mathrm{4.7833...}{\text{g cm}}^{-3}$$

According to the rules of significant figures, when performing division, the final result must be rounded off to have the same number of significant figures as the measurement with the least number of significant figures.
Here, the volume (1.2 cm³) has only 2 significant figures, which is less than the mass (3 significant figures). Therefore, the final density must be rounded to 2 significant figures.

Rounding 4.7833... to two significant figures, we look at the third digit (8), which is greater than 5. Thus, we round up the second digit (7) by 1, giving us:
$$\text{Density}=4.8{\text{g cm}}^{-3}$$