pH meter electrode protection solution configuration
The chemical name of PH electrode protection solution potassium chloride is KCL, its molecular weight = 74.551 white crystal or crystalline powder. It has a bitter and salty taste. Hygroscopic, sealed and kept dry. One liter = 1000 milliliters (1000ML) 3mol/L potassium chloride solution - that is to say, each liter of the solution contains 3 moles of potassium chloride, mol (mole) is a stoichiometric unit, and the mass value of each mol substance is equal to the substance The relative molecular mass of 3mol/L KCl is about 223.5g KCl per liter.
Quickly configure pH meter | acidity meter protection solution - 3mol/L KCl solution Expansion steps:
1. Calculation: KCl molar mass is 74.5g/mol, then KCl mass=3mol×74.5g/mol=223.5g;
2. Weighing: Weigh KCl 223.5g with an analytical balance, pay attention to the use of the analytical balance;
3. Dissolving: Dissolve it completely with 100ml distilled water in a beaker, and stir with a glass rod;
4. Transfer and washing: transfer the dissolved solution into a 1000ml volumetric flask, and use a volumetric flask with a narrow mouth;
Note: In order to prevent the solution from spilling, and at the same time, do not let the solution flow down the bottle wall above the scale line, use a glass rod for drainage. In order to ensure that the solute is transferred to the volumetric flask as completely as possible, the beaker and glass rod should be washed with distilled water two or three times, and the solution after each washing should be poured into the volumetric flask. Gently shake the volumetric flask to mix the solution thoroughly; (use a glass rod for drainage)
5. Constant volume: When adding water to 2-3 cm close to the scale, use a rubber dropper to add distilled water to the scale. This operation is called constant volume. When constant volume, pay attention that the lowest point of the concave liquid surface of the solution is tangent to the scale line, and the eyesight is horizontal to the scale line, and you can’t look down or look up, otherwise it will cause errors;
6. Shake well: the concentration of the solution after constant volume is not uniform, the cork of the volumetric flask should be tightly plugged, and the cork should be held up with the index finger, and the bottom of the bottle can be supported by the fingers of the other hand, and the volumetric flask should be turned upside down and shaken several times , to mix the solution evenly. This operation is called shaking;
7. Shake the KCl solution after constant volume. Pour the prepared solution into the reagent bottle, cap the bottle, and label it. This is a 3mol/L KCl solution.
The potassium chloride used to soak the electrode can be saturated solution. The easiest way is to add some distilled water (such as 100g/or 100ml) to the beaker, and then add potassium chloride while stirring until it can no longer be dissolved. Potassium chloride is considered saturated. The concentration of potassium chloride used to soak the electrode is 3mol/L. According to the conversion, there are 223.5 grams of potassium chloride in 1000 mg of solution.
