Question

The density of alcohol is $800Kg{m^{ - 3}}$ . Its relative density is:
A.8
B.0.8
C.0.08
D.800

Answer 1

Basically, the relative density is defined as the ratio of the density of the substance to the density of water. So, to solve this question, we will find the ratio of density of alcohol to the density of water by using the formula and substituting the values.

Formula used:
Relative density $= \dfrac{{density\,of\,alcohol}}{{density\,of\,water}}$

Complete step by step answer:
Basically, density refers to the amount of mass in a unit volume of matter and every substance has a different density. Now, let’s discuss relative density. It is defined as the ratio of density of the substance to the density of water. It is also known as specific gravity. The density of the substance varies with temperature and pressure. There are various methods which are used to determine the relative density of any substance based on its type. Some of the methods are listed below:
1.Buoyancy method
2.Hydrometer
3.Hydrostatic balance
4.Immersed body method
Now, we have been given the density of alcohol and we need to find its relative density. So according to the formula,
Relative density $= \dfrac{{density\,of\,alcohol}}{{density\,of\,water}}$
Now, density of water is $1gc{m^{ - 3}}$ which is further equal to ${10^3}kg{m^{ - 3}}$
Now, by substituting the values we get,
Relative density $= \dfrac{{800}}{{1000}}$
=0.8
Hence, option B is correct.

Note: There are various factors which influence the measurement of relative density. Some of the factors are air bubbles, temperature, solid matter sample etc. Temperature is one of the major factors as change in temperature affects the liquids to a greater extent and hence results in change in density of the liquid.