In this question, we have the following reaction:
CaCl2 + K2CO3 -> CaCO3 + 2 KCl
We have:
CaCl2 = 0.0255 M
K2CO3 = 0.0298 Liters and 0.107 M
Now, according to the molar ratio, we need 1 mol of CaCl2 for every mol of K2CO3 in order to react, therefore we need to find the number of moles of K2CO3 in order to find the number of moles of CaCl2 and then we will find the volume
To find the number of moles, we will be using the molarity formula:
M = n/V
For K2CO3:
0.107 = n/0.0298
0.003189 moles of K2CO3
And according to the molar ratio it will be the same number of moles of CaCl2, now we use this value in the molarity formula again, but now to find the volume of CaCl2
M = n/V
0.0255 = 0.003189/V
V = 0.125 L or 125 mL