Question

The symbol of S.I unit of amount of substance is:
(a)mole
(b)density
(c)equivalent weight
(d)molecular weight

Answer 1

Hint: The International System of Units is the metric system which is used universally as a standard for measurements. It is abbreviated as the S.I unit system. The S.I unit of substance is related to Avogadro number of elementary entities.

Complete answer:
-International System of Units is a modern form of metric system and is abbreviated as SI unit system. Every country in the world follows this system of measurements.
-SI unit system consists of a coherent system of measurement of units starting with seven basic units. These basic units are,
-For time, the SI unit is seconds and represented as s.
-For length, it is in meters and represented as m.
-SI unit of mass is kilograms (kg).
-For electric current is amperes (a).
-For temperature, the SI unit is K or Kelvin.
-For amount of substance, the SI unit is mole and is represented as mol.
-And for luminous intensity is candela (cd).
These seven units are called the base units. All the other units are derived from these seven units and those are called derived units. For example, SI units of speed is meter per second, m/s derived from the base units meter and second. There are 22 derived units which are provided with special names and symbols.
Thus, the S.I unit for the amount of substance is mole and is represented as mol.

The correct answer to the question is option (a).

Note:
S.I unit system is accepted all over the world. Before the S.I unit system, CGS system or the centimetre-gram-second system was used. The CGS unit system has many flaws such as lack of coordination between various disciplines used and the inconsistency between the systems of electrostatic units and electromagnetic units. Thus, the S.I unit is preferred.