Question

How many litres of ammonia gas at S.T.P. would be needed to prepare 100 mL of 2.5 M ammonium hydroxide solution ?

Answer 1

NH3+H2O--> NH4OH

ATQ :-

2,5=x/35 × 1000÷100

where x is the molecular weight of Ammonium Hydroxide [NH4OH]

by solving, we get x = 8.75.

Now, moles of NH4OH is 8.75 / 35 = 0.25.

By comparing

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One mole of NH4OH is produced when One mole of NH3 reacts with One mole of H20

=> 0.25 moles of NH4OH is produced when 0.25 moles of NH3 reacts with x Moles of H20 [maybe 0.25]. 

Thus 0.25 moles of NH3 is 0.25 * 22.4 litres of NH3 

After Solving

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=> 5.6 litres of NH3 is needed to prepare 100ml of 2.5M Ammonium Hydroxide Solution.