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The question is taken from an engineering entrance exam in India(JEE 2024)

If 3 mole of aniline is reacted with one equivalent of benzene diazonium chloride the maximum amount of aniline yellow formed will be ?

My attempt : Aniline reacts with Benzene diazonium chloride to give a yellow dye para amino azo-benzene

From the balanced chemical equation, it is clear that 1 mole of benzene diazonium chloride reacts with 1 mole of aniline Since the problem states we have 1 equivalent of Benzene Diazonium chloride I thought we had one mole of it{ I searched on internet for meaning of One Equivalent in organic reactions and found this definition }

Hence by the concept of limiting reagent we should get only 1 mole of dye.But the official answer key given is 3 moles of dye

Any help in this problem will be highly appreciated as this question is from an important exam

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This question was discussed previously here Terminology. The jargon of equivalents in organic synthesis is certainly not the best choice, because it is not related to the normality concept used in analytical chemistry or biochemistry, but only organic chemists use a different shade with a specific meaning.

If we attach the word "molar" before equivalents, then the statement becomes crystal clear. So "If 3 mole of aniline is reacted with one equivalent of benzene diazonium chloride the maximum amount of aniline yellow formed will be___?"

can be interpreted as "If 3 mole of aniline is reacted with one molar equivalent of benzene diazonium chloride the maximum amount of aniline yellow formed will be 3", which is the answer in your book.

As demonstrated in the glossary maintained by UCLA website you shared: Link

In chemical stoichiometry, the amount of one substance required to completely consume one mole of another functional group or substance

enter image description here In this catalytic hydrogenation of 2-butyne (an alkyne), the first equivalent of H2 reduces the alkyne to Z-2-butene. The second equivalent of H2 reduces the alkene to butane (an alkane).

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[OP] From the balanced chemical equation, it is clear that 1 mole of benzene diazonium chloride reacts with 1 mole of aniline

Yes, so 3 moles of benzene diazonium chloride reacts with 3 moles of aniline.

[OP] Since the problem states we have 1 equivalent of Benzene Diazonium chloride I thought we had one mole of it.

In organic chemistry jargon, "equivalent" is a relative amount. Two equivalents means it is in (two-fold) excess, 0.1 equivalent means it is limiting (unless it refers to a catalyst), and one equivalent means that the two reactants are present in stoichiometric amounts (neither is limiting).

The reason for writing it like this is to make it easier to adapt a recipe to a different starting amount. Often, one of the reactants is obtained from a previous step and you want to use all of it, giving rise to arbitrary amounts of starting material.

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