Equivalent weight is defined as the weight that will react with, displace, or is equivalent to one gram of hydrogen.

Equivalent weight is defined as the weight that will react with, displace, or is equivalent to one gram of hydrogen.

• A. The weight that will react with, displace, or is equivalent to one gram of hydrogen
• B. The weight required to produce a precipitate in a neutral solution
• C. Half the molecular weight of the compound
• D. Number of grams needed to titrate 1 liter of solution

Answer: (A)

Equivalent weight is a measure of how much of a substance reacts in a given chemical change, defined as the amount that will react with, displace, or be equivalent to one gram of hydrogen. That one-gram hydrogen reference is what links mass to reactive capacity across acid-base, redox, and precipitation reactions. Practically, the equivalent weight equals the molar mass divided by the valence factor—the number of hydrogen atoms it can replace or the number of electrons transferred in the reaction. This is why the statement is correct: it directly states the standard definition—mass that reacts with one gram of hydrogen. It also ties neatly to how we use equivalents in calculations: for an acid, base, or oxidizing/reducing agent, the equivalent weight tells you how much of the substance provides one equivalent of reactive capacity. To see why the other ideas aren’t the general definition: the amount needed to produce a precipitate in a neutral solution describes a specific reaction outcome rather than a universal measure of reactive capacity. Half the molecular weight would only be true in a very particular case (where the valence is two in that reaction) and isn’t a general rule. The notion of grams required to titrate 1 liter of solution relates to normality and concentration in a titration, not the fundamental definition of an equivalent weight.

Equivalent weight is a measure of how much of a substance reacts in a given chemical change, defined as the amount that will react with, displace, or be equivalent to one gram of hydrogen. That one-gram hydrogen reference is what links mass to reactive capacity across acid-base, redox, and precipitation reactions. Practically, the equivalent weight equals the molar mass divided by the valence factor—the number of hydrogen atoms it can replace or the number of electrons transferred in the reaction.

This is why the statement is correct: it directly states the standard definition—mass that reacts with one gram of hydrogen. It also ties neatly to how we use equivalents in calculations: for an acid, base, or oxidizing/reducing agent, the equivalent weight tells you how much of the substance provides one equivalent of reactive capacity.

To see why the other ideas aren’t the general definition: the amount needed to produce a precipitate in a neutral solution describes a specific reaction outcome rather than a universal measure of reactive capacity. Half the molecular weight would only be true in a very particular case (where the valence is two in that reaction) and isn’t a general rule. The notion of grams required to titrate 1 liter of solution relates to normality and concentration in a titration, not the fundamental definition of an equivalent weight.