Question

If $1$ stands for true and $0$ stands for false, then choose the correct code for the following statement:
End point in the titration of $CuS{O}_4$ iodometrically (with starch as the indicator) is the disappearance of blue color.

Answer 1

The end point in the titration of $CuS{O}_4$ iodometrically (with starch as the indicator) is the disappearance of blue color.
The reactions involved are as follows.
$2C{u}^{2+}+4I^{-}\to 2CuI\left(s\right)+I_2$
$2S_2{O}_3^{2-}+I_2\to S_4{O}_6^{2-}+2I^{-}$
The blue colour is due to formation of complex of iodine with starch. At the end point, iodine is completely reacted with sodium thiosulphate solution. Hence, the blue colour disappears.