4.5 Quantitative Chemical Analysis

Titration of a 20.0-mL sample of acid rain required 1.7 mL of 0.0811 M NaOH to reach the end point. If we assume that the acidity of the rain is due to the presence of sulfuric acid, what was the concentration of sulfuric acid in this sample of rain?

In a common medical laboratory determination of the concentration of free chloride ion in blood serum, a serum sample is titrated with a Hg(NO₃)₂ solution.
$2 \text{Cl}^{−} \left(a q\right) + \text{Hg} \left(\text{NO}_{3}\right)_{2} \left(a q\right) \rightarrow 2 \text{NO}_{3} ^{−} \left(a q\right) + \text{HgCl}_{2} \left(s\right)$

What is the Cl⁻ concentration in a 0.25-mL sample of normal serum that requires 1.46 mL of 8.25 $\times$ 10⁻⁴ M Hg(NO₃)₂(aq) to reach the end point?

A sample of gallium bromide, GaBr₃, weighing 0.165 g was dissolved in water and treated with silver nitrate, AgNO₃, resulting in the precipitation of 0.299 g AgBr. Use these data to compute the %Ga (by mass) GaBr₃.

A 0.025-g sample of a compound composed of boron and hydrogen, with a molecular mass of ~28 amu, burns spontaneously when exposed to air, producing 0.063 g of B₂O₃. What are the empirical and molecular formulas of the compound?

What volume of 0.600 M HCl is required to react completely with 2.50 g of sodium hydrogen carbonate?
$\text{NaHCO}_{3} \left(a q\right) + \text{HCl} \left(a q\right) \rightarrow \text{NaCl} \left(a q\right) + \text{CO}_{2} \left(g\right) + \text{H}_{2} \text{O} \left(l\right)$

What volume of a 0.3300-M solution of sodium hydroxide would be required to titrate 15.00 mL of 0.1500 M oxalic acid?
$\text{C}_{2} \text{O}_{4} \text{H}_{2} \left(a q\right) + 2 \text{NaOH} \left(a q\right) \rightarrow \text{Na}_{2} \text{C}_{2} \text{O}_{4} \left(a q\right) + 2 \text{H}_{2} \text{O} \left(l\right)$

A sample of solid calcium hydroxide, Ca(OH)₂, is allowed to stand in water until a saturated solution is formed. A titration of 75.00 mL of this solution with 5.00 $\times$ 10⁻² M HCl requires 36.6 mL of the acid to reach the end point.
$\text{Ca} \left(\text{OH}\right)_{2} \left(a q\right) + 2 \text{HCl} \left(a q\right) \rightarrow \text{CaCl}_{2} \left(a q\right) + 2 \text{H}_{2} \text{O} \left(l\right)$

What is the molarity?

How many milliliters of a 0.1500-M solution of KOH will be required to titrate 40.00 mL of a 0.0656-M solution of H₃PO₄?
$\text{H}_{3} \text{PO}_{4} \left(a q\right) + 2 \text{KOH} \left(a q\right) \rightarrow \text{K}_{2} \text{HPO}_{4} \left(a q\right) + 2 \text{H}_{2} \text{O} \left(l\right)$

The reaction of WCl₆ with Al at ~400 °C gives black crystals of a compound containing only tungsten and chlorine. A sample of this compound, when reduced with hydrogen, gives 0.2232 g of tungsten metal and hydrogen chloride, which is absorbed in water. Titration of the hydrochloric acid thus produced requires 46.2 mL of 0.1051 M NaOH to reach the end point. What is the empirical formula of the bla…