A normal solution is:
one gram equivalent mass of the substance in one liter solution
Explanation of the correct option:
(B) One normal solution is the solution that contains one gram equivalent mass of the substance in one liter solution.
Explanation of the incorrect options:
(A) A solution whose concentration is known is known as a standard solution.
(C) A normal solution contains one gram equivalent mass of the substance in 1000 mL of the solution instead of 1 mL solution.
(D) One gram molecular mass of the substance in one liter solution makes one molar solution instead of one normal solution.
Hence, option (B) is correct.