Answer to Question #98097 in General Chemistry for Adeleke Oluwatobi

Question

A is a solution containing 4.8gram of an acid Hx per dm cube .B is a solution containing 0.025 moles of anhydrous trioxocarbonate 4 per dm cube of solution. 25 cm cube portion of solution B required an average of 26.40cm cube of solution A for complete neutralization using methylorange as an indicator
From the question write a balanced equation for the reaction
Calculate the molar concentration of solution A
Calculate relative molar mass of A

Answer 1

Solution.

Since methyl orange is used as an indicator, the reaction proceeds to the formation of carbonic acid (carbon dioxide and water).

$CO3^{2-} + 2H^+ = H2O + CO2$

And in the problem it is said that there was a complete neutralization of the acid, the amount of substance anhydrous trioxocarbonate 4 is equal to the amount of substance acid Hx.

$n(H^+) = 2 \times n(CO3^{2-})$

$n(CO3^{2-}) = C(CO3^{2-}) \times V(CO3^{2-})$

$n(CO3^{2-}) = 0.025 \times 0.025 = 6.25*10^{-4} \ mol$

$n(H^+) = 12.5*10^{-4} \ mol$

The total volume of the system is equal to:

$V = V1 + V2 = 0.0514 \ L$

$C(Hx) = \frac{12.5*10^{-4}}{0.0514} = 0.024 \ M$

$C(Hx) = \frac{m}{M \times V}$

$M(Hx) = \frac{m}{C \times V}$

$m(Hx) = 4.8 \times 0.0264 = 0.127 \ g$

M(Hx) = 102.95 g/mol

Answer:

C(Hx) = 0.024 M

M(Hx) = 102.95 g/mol