Question

For the following reaction, 24.5 grams of diphosphorus pentoxide are allowed to react with 13.3 grams of water.

diphosphorus pentoxide (s) + water (l) -> phosphoric acid (aq)

what is the maximum mass of phosphoric acid that can be formed? _____ grams

what is the formula for the limiting reagent? ________________

what mass of the excess reagent remains after the reaction is complete? _______ grams

Answer 1

​​​​​Answer:-

1. Maximum mass of phosphoric acid formed = 33.82 g

2. Limiting reagent :- P₂O₅ (diphosphorous pentoxide)

3. Mass of excess reagent (H₂O) remaining after the reaction completed :- 3.98 g

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Explanation :-

The balanced equation for reaction between diphosphorus pentoxide (P₂O₅) and water (H₂O) to for phosphoric acid (H₃PO₄) is

.....(1)

Given:-

  

From reaction (1) it is observed that,

  

i.e.  

therefore,

since, we have 13.3 g H₂O and we required 9.32 g H₂O.

Therefore, H₂O is in excess and it is excess reagent.

While P₂O₅ is limiting reagent.

Since, Out of 13.3 g H₂O 9.32 g H₂O is consumed during reaction.

Therefore, mass of H₂O (excess reagent) remaining after reaction is complete is

= [13.3 (g) - 9.32 (g) ] = 3.98 (g)

  

Now,

mass of product is always calculated from limiting reagent.

Therefore, mass of phosphoric acid calculated from diphosphorous pentoxide.

From reaction (1) it is observed that

i.e.

therefore,

Thus,

Maximum 33.82 g mass of phosphoric acid will be formed.