Question

Consider the balanced chemical equation,

MgCl2(aq) + 2AgF(aq) → 2AgCl(s) + MgF2(aq)


If both reactants are completely consumed and we produce 20 formula units of AgCl, how many ions of Mg and F did we start with?

Answer 1

Answer: we started with 10 ions of Mg and 20 ions of F.

Step-by-step explanation: The given balanced equation is:

`MgCl_2(aq)+2AgF(aq)\rightarrow 2AgCl(s)+MgF_2(aq)`

From this balanced equation, 2 formula units of AgCl are formed by 2 formula units of AgF and 1 formula unit of
`MgCl_2` .

From here, the ratio between AgCl and AgF is 2:2 that is 1:1 and the ratio between AgCl and
`MgCl_2` is 2:1 ,

Since the ratio between AgCl and AgF is 1:1, 20 formula units of AgCl will be formed by 20 formula units of AgF.

The ratio between AgCl and
`MgCl_2` is 2:1, so 20 formula units of AgCl will be formed by 10 formula units of
`MgCl_2` .

One formula unit of
`MgCl_2` contains one ion of Mg, so 10 formula units of
`MgCl_2` will contain 10 ions of Mg.

Similarly, 1 formula unit of AgF contains one ion of F, so 20 formula units of AgF will contain 20 ions of F.

So, we started with 10 ions of Mg and 20 ions of F to make 20 formula units of AgCl.

Answer 2

We started with twenty ions of Mg and twenty ions of F. Producing 20 units of AgCl requires twenty MgCl2 since it is the only source of magnesium. Similarly it requires twenty AgF since it is the only source of silver.