Question

a stock solution of hydrochloric acid (hcl) supplied by a certain vendor contains small amounts of several impurities, including copper and nickel. let x denote the amount of copper and let y denote the amount of nickel, in parts per ten million, in a randomly selected bottle of solution. assume that the joint probability density function of x and y is given by

Answer 1

The concentration of the original hydrochloric acid solution sample can be calculated using the volume of sodium hydroxide solution used in the titration. In this case, the concentration is 0.1234 M.

Step-by-step explanation:

The concentration of the original hydrochloric acid solution sample can be calculated using the volume of the sodium hydroxide solution used in the titration. In this case, the volume of sodium hydroxide solution at the endpoint is 31.416 mL or 0.031416 L. The molar concentration of the sodium hydroxide solution is given as 0.1234 M. According to the balanced chemical equation between hydrochloric acid (HCl) and sodium hydroxide (NaOH), the mole ratio is 1:1. Therefore, the number of moles of HCl in the 0.031416 L of sodium hydroxide solution is equal to the concentration of the sodium hydroxide solution. So, the concentration of the original hydrochloric acid solution sample is 0.1234 M.

Answer 2

Titration with a 0.1234 M sodium hydroxide solution to find the unknown concentration of hydrochloric acid. The calculation based on 31.416 mL of the titrant used indicates that the concentration of the hydrochloric acid solution is 0.019385 M.

Step-by-step explanation:

To determine the concentration of the original hydrochloric acid solution, we must understand the process of titration. In titration, a solution of known concentration (titrant) is used to determine the concentration of an unknown solution. The point at which the reaction between the titrant and the unknown solution is complete is known as the endpoint, indicated by the phenolphthalein changing color.

The student used 31.416 mL (or 0.031416 liters) of a 0.1234 M sodium hydroxide solution to titrate a 200 mL sample of hydrochloric acid. To find the number of moles of sodium hydroxide used, we multiply its volume by its molarity:

Number of moles of NaOH = 0.031416 liters × 0.1234 mol/liters = 0.003877 mol of NaOH

Since hydrochloric acid (HCl) and sodium hydroxide (NaOH) react in a 1:1 molar ratio, the moles of HCl in the unknown solution is also 0.003877 mol. To find the concentration of HCl in the original solution, we divide the moles of HCl by the volume of the sample in liters:

Concentration of HCl = 0.003877 mol / 0.200 liters = 0.019385 M.

The concentration of the original hydrochloric acid solution sample was, therefore, 0.019385 M.