Chromium and copper (ii) sulfate react according the reaction below;
2Cr + 3CuSO4 = 3Cu +Cr2(SO4)3
We can calculate the number of moles of CuSO4 present;
no of moles of CuSO4 = 0.75 × 0.125 = 0.09735 moles
According to the reaction the mole ratio is 2 : 3
Moles of Chromium = (0.09735 × 2)/3
= 0.0625 Moles
Mass of chromium = 0.0625 moles × 52 g/mole
= 3.25 g of chromium