Question

If 4.8 moles of X and 3.4 moles of Y react according to the reaction below, how many moles of the excess reactant will be left over at the end of the reaction?

3X + 2Y “yields”/ X3Y2

1.7 mol Y left over
1.6 mol X left over
0.2 mol Y left over
0.1 mol X left over

Answer 1

The correct answer is : '0.2 mol Y left over'.

Step-by-step explanation:

`3X + 2Y \rightarrow  X_3Y_2`

Moles of X = 4.8 moles

Moles of Y = 3.4 moles

According to reaction, 3 moles of X react with 2 moles of Y .

Then 4.8 moles of X react with :

`(2)/(3)* 4.8=3.2`moles of Y

Moles of Y reacted = 3.2 moles

Moles of Y left unreacted = 3.4 moles - 3.2 moles = 0.2 moles

As we can see that X is in limiting amount and y is present in an excessive amount.And the left over amount of Y is 0.2 moles.

Answer 2

Answer : The correct option is, 0.2 mole Y left over .

Explanation : Given,

Moles of X = 4.8 mole

Moles of Y = 3.4 mole

The balanced chemical reaction is,

`3X+2Y\rightarrow X_3Y_2`

From the balanced reaction, we conclude that

As, 3 moles of X react with 2 moles of Y

So, 4.8 moles of X react with
`(2)/(3)* 4.8=3.2` moles of Y

From this we conclude that, the reactant Y is an excess reagent and X is a limiting reagent.

The moles of excess reagent left over at the end of the reaction = Given moles of X - Required moles of X

The moles of excess reagent left over at the end of the reaction = 3.4 - 3.2 = 0.2 mole

Therefore, the moles of excess reagent left over at the end of the reaction is, 0.2 mole Y left over.