Question

The titration of 15.00 mL of hydrobromic acid required 22.96 mL of a 0.1853 M calcium hydroxide to reach the endpoint. Calculate the concentration of the hydrobromic acid

Answer 1

Answer:

0.57 M

Explanation:

We have to start with the reaction:

$HBr~+~Ca(OH)_2~->~H_2O~+~CaBr_2$

Now we have to balance the reaction:

$2HBr~+~Ca(OH)_2~->~2H_2O~+~CaBr_2$

The next step is the calculation of the number of moles of Calcium Hydroxide, so:

$M=\frac{#~mol}{L}$

If we use the amount of volume in "L" (22.96 mL=0.02296 L), so:

$0.1853~M~=\frac{#~mol}{0.02296~L}$

$#~mol=~0.1853*0.02296=~0.00425~mol~Ca(OH)_2$

Now, with the balanced reaction we can find the moles of HBr, so:

$0.00425~mol~Ca(OH)_2\frac{2~mol~HBr}{1~mol~Ca(OH)_2}=0.0085~mol~HBr$

Finally, with the volume in liters (15.00 mL= 0.015L) we can find the molarity, so:

$M=\frac{0.0085~mol~HBr}{0.015~L}=0.57~M$

The concentration of HBr is 0.57 M