Question

If 45.0 mL of a 0.0500 M HNO3, 10.0 mL of a 0.0500 M KSCN, and 30.0 mL of a 0.0500 M Fe(NO3)3 are combined, what is the initial concentration of SCN- in the mixture?

Answer 1

the initial concentration of SCN- in the mixture is 0.00588 M

Step-by-step explanation:

The computation of the initial concentration of the SCN^- in the mixture is as follows:

As we know that

`KSCN \rightarrow K^ + SCN^-`

As it is mentioned in the question that KSCN is present 10 mL of 0.05 M

So, the total milimoles of SCN^- is

= 10 × 0.05

= 0.5 m moles

The total volume in mixture is

= 45 + 10 + 30

= 85 mL

Now the initial concentration of the SCN^- is

= 0.5 ÷ 85

= 0.00588 M

hence, the initial concentration of SCN- in the mixture is 0.00588 M