Question

How many milliliters of 0.02 M HCl are needed to react completely with 100 mL of 0.01 M NaOH?

A) 200 mL
B) 100 mL
C) 75 mL
D) 50 mL
E) 25 mL

Answer 1

The reaction of HCl and NaOH is HCl + NaOH = NaCl + H2O. So the mole number of HCl and NaOH is equal. So the volume of HCl =0.01*0.1/0.02=0.05 L =50 ml. So the answer is D).

Answer 2

Answer: Option (D) is the correct answer.

Step-by-step explanation:

Molarity is number of moles divided by volume of the solution.

Mathematically, Molarity =
`(no. of moles)/(Volume)`

Also, in the given situation number of moles of both HCl and NaOH are equal. Therefore, volume of HCl will be calculated as follows.

`M_(HCl)V_(HCl)` =
`M_(NaOH)V_(NaOH)`

`0.02 M * V_(HCl)` =
`0.01 M * 100 mL`

`V_(HCl)` =
`(0.01 M * 100mL)/(0.02)`

= 50 mL

Thus, we can conclude that volume of HCl is 50 mL.