Suggest other suitable indicators for determination of calcium trioxocarbonate (iv) content in chalk by back titration

Answer 1

First, you should know that calcium trioxocarbonate (iv) is not an IUPAC name for CaCO3.
Second, "other" suitable indicators means what? What indicator(s) have you already used or suggested. The indicator you use depends somewhat on the acid used and what base you back titrate with.