Commercially available concentrated Hcl contains 38% Hcl by mass. (1) what is the molarity of the solution ( density of solution =1.19 g mL -1)? (2) What volume of concentrated Hcl is required is required to make 1.0 L of an 0.10 M Hcl?

1 Answer
Jul 1, 2017

Molarity = 12.61 Molar and 7.96 ml of HCl(38%) needed for 1.0 Liter of 0.10 Molar HCl(aq).


Question 1:
#HCl(38%) = ((38 g HCl)/(100g"Soln")) = ((?"moles""HCl")/(1.0 "Liter""Solution"))#

=> Moles of HCl in 38 grams = #((38 g HCl)/(36(g/"mol")))=1.06 "mole"HCl#

=> Volume of Solution (Liters) containing 1.06 mole of HCl

= #(100gHCl(38%))/(1.19(g/"ml"))= 84.03 mlHCl(38%) = 0.084LHCl(38%)#

=> Molarity HCl(38%) = #(1.06"mole""HCl")/(0.084L"HCl""Conc") = 12.62 Molar HCl(aq)#

Question 2:
Use the solution prep equation for liquid mfg stock.
Volume of Liquid Mfg Stock needed in milliliters ...

=> Vol of Mfg Stock = #(("Molarity)("Volume)("formula" "Weight"))/((Purity)("Specific" Gravity))#

=> #((0.10M)(1.0L)(36(g/"mole")))/((0.38)(1.19(g/"ml"))) = 7.96 ml of HCl(38%)#

MIXING: Add 7.96 ml of HCL(38%) into a small quantity of water, mix to disperse; then dilute with solvent water up to but not to exceed the total needed volume of solution (in this case 1.00 Liter). => 1.0 Liter of 0.10 Molar HCl(aq) Solution. => Verify concentration with standardized NaOH(solution).

MIXING CAUTION: Always add a concentrated strong acid into a small quantity of water, mix to disperse; then dilute up to, but not to exceed needed total volume of solution.

Water onto bulk strong concentrated acid may result in uncontrolled heat generation and flash boiling due to accelerated ionization rate.

Certainly wear protective eye ware and appropriate clothing.