Calculate amount of Nitrogen in one bag (50 kg) of Urea.

Calculate percentage of platinum in [(NH₄)₂ PtCl₆]. Ammonium chloride platinate in nearest whole number.

Assertion (A): The atomic mass of sodium is 23 amu.

Reason (R): An atom of sodium is 23 times heavier than an atom of carbon with mass 12 amu.

1. Both A and R are true and R is the correct explanation of A.
2. Both A and R are true but R is not the correct explanation of A.
3. A is true but R is false.
4. A is false but R is true.

Assertion (A): An atom is the smallest part of matter which can take part in a chemical reaction.

Reason (R): Atoms of every element can exist independently.

1. Both A and R are true and R is the correct explanation of A.
2. Both A and R are true but R is not the correct explanation of A.
3. A is true but R is false.
4. A is false but R is true.