How many grams of NaOH should be dissolved in 1 litre of solution to prepare a solution with pH value12
pH = 12
pOH = 14-12 = 2
OH^- = 1 x 10^-2
Therefore, (NaOH) = 1 x 10^-2 M - 0.01 moles/L
moles = grams/molar mass. You know moles and molar mass, calculate grams.
To determine the number of grams of NaOH required to prepare a solution with a pH value of 12, we need to understand the relationship between pH, concentration, and dissociation of the base.
The pH scale is a measure of the concentration of hydrogen ions (H+) in a solution. A pH value of 7 represents neutrality, while values below 7 indicate acidity, and values above 7 represent alkalinity or basicity. The pH scale is logarithmic, meaning that each whole number change in pH represents a tenfold difference in acidity or basicity.
NaOH (sodium hydroxide) is a strong base that dissociates fully in water, which means it releases all of its hydroxide ions (OH-) into the solution. The hydroxide ions then react with water to produce hydroxide ions (OH-) and hydrogen ions (H+), resulting in an alkaline solution.
To calculate the number of grams of NaOH required, we need to consider the concentration of hydroxide ions needed to achieve a pH of 12.
1. The pH scale can be converted to a hydrogen ion concentration by taking the antilog (-log) of the pH value. In this case, the antilog of pH 12 is 10^-12, which gives us a hydrogen ion concentration of 1x10^-12 M.
2. Since NaOH dissociates fully in water, we can assume that the concentration of hydroxide ions (OH-) is equal to the concentration of sodium hydroxide (NaOH). Therefore, we need to prepare a 1x10^-12 M solution of NaOH.
3. To convert from molarity (M) to grams per liter (g/L), we need to know the molar mass of NaOH, which is approximately 40 g/mol.
4. The formula for converting molarity to grams per liter is:
grams per liter (g/L) = molarity (M) x molar mass (g/mol) x volume (L)
In this case, the volume is given as 1 liter (L), so the calculation becomes:
grams of NaOH = 1x10^-12 M x 40 g/mol x 1 L
= 4x10^-11 g
Therefore, approximately 4x10^-11 grams of NaOH should be dissolved in 1 liter of solution to prepare a solution with a pH value of 12.