Final answer:
To calculate the normality of a 36.5% concentrated HCl solution with a density of 1.25 g/cm³, convert the volume of 1 liter to mass using the provided density, calculate the mass of HCl present using the percentage by mass, and then convert that mass to moles. Knowing that HCl is monoprotic, the normality equals the moles of HCl per liter, resulting in a normality of 12.51 N.
Step-by-step explanation:
The question involves calculating the normality of a concentrated HCl solution given its mass percentage and density. HCl (hydrochloric acid) has a molar mass of 36.46 g/mol and is a monoprotic acid, meaning each mole of HCl will donate one mole of H+ ions.
To calculate the normality, we first need to determine how many grams of HCl are in 1 liter of the solution. We can use the density (1.25 g/cm³) to convert this volume to mass, since 1 L is 1000 cm³:
1000 cm³ * 1.25 g/cm³ = 1250 g of HCl solution
Given that the solution is 36.5% HCl by mass:
1250 g * 0.365 = 456.25 g of HCl
Now, we convert the mass of HCl to moles:
456.25 g / 36.46 g/mol = 12.51 moles of HCl
Since normality is the number of equivalents per liter of solution, and each mole of HCl provides 1 equivalent of H+ ions (being monoprotic), the normality is:
12.51 moles / 1 L = 12.51 N
The normality of the concentrated HCl solution is therefore 12.51 N.