V. Determination of sulfuric acid content
The sulfuric acid solution can neutralize the sulfuric acid.
2NaOH+H ₂ S0 ₄ ===Na ₂ S0 ₄十 2H ₂ O
Pipette about 1mL of sulfuric acid, put it into a small weighing bottle of known quality, accurately weigh (accurate to 0.0001g), carefully transfer it into a beaker containing 100mL of distilled water, wait until the solution is cooled to room temperature, add 2 drops Methyl orange was titrated to a yellowish orange color with a 1 mol/L sodium hydroxide standard solution while stirring with a glass rod.

Wherein ωH ₂ SO ₄ - the mass fraction of sulfuric acid, %;
c (NaOH)----the concentration of the substance of the sodium hydroxide standard solution, mol / L;
V----the volume of sodium hydroxide solution consumed, mL;
m----the quality of sulfuric acid, g;
0. 09808---- molar mass of sulfuric acid, kg / mol.
6. Determination of solid sodium hydroxide
Accurately weigh about 3g of sodium hydroxide with a known quality weighing bottle, place it in a 200mL beaker, add a small amount of water to dissolve, transfer to a 100mL volumetric flask, dilute to the mark with water, shake and set aside.
Pipette 25mL of test solution, in a 30mL Erlenmeyer flask, add 10mL 10% cesium chloride solution, add 30mL of water, shake for a while, add 2-3 drops of phenolphthalein indicator, titrate with 1mol / L hydrochloric acid standard solution until the solution is yellow Turning orange red is the end point.

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Where ωNaOH----sodium hydroxide mass fraction, %;
c(HCl)----the concentration of the substance of the hydrochloric acid standard solution, mol / L;
V----volume the volume of hydrochloric acid standard solution, mL;
V ₁ ---- total volume of test solution, mL;
V ₂ ---- the volume of the test solution, mL;
m----sample quality, g;
0.040---- molar mass of sodium hydroxide, kg/mol.
7. Determination of potassium carbonate content
Since the weakly alkaline medium, a potassium ion can be quantitatively formed a white potassium tetraphenyl boron to sodium tetraphenylborate precipitate.
K ⁺ +[B(C ₆ H ₆ ) ₄ ]-===K[B(C ₆ H ₅ ) ₄ ]↓
Weigh 0.45-0.5g of the dried sample (accurate to 0. 0002g), dissolve in a 200mL volumetric flask, dilute to the mark with water, shake well, if the solution is turbid, filter with dry filter paper. Lmol/L sodium tetraphenylborate was added dropwise. lmol/L sodium tetraphenylborate was added dropwise. The solution was added to a 100 mL beaker, and 40 mL of water was added. The pH was adjusted to 8-10 with 1:1 hydrochloric acid and 10% sodium hydroxide solution. 5 mL of the solution was stirred for 5 min, filtered through a constant mass of No. 5 glass crucible, washed several times with a saturated solution of sodium tetraphenylborate, washed twice with water, and dried at 120 ° C until the mass was constant.

Where ωK ₂ CO ₃ ---- mass fraction of potassium carbonate, %;
M1----the mass of potassium tetraphenylborate precipitate, g;
m----the mass of the sample, g;
0.1091---- molar mass ratio of potassium to potassium tetraphenylborate;
1. 7674---- molar ratio of potassium carbonate to potassium.
Eight, determination of carbonic acid content
A weighing bottle of known mass accurately weighed 0. 2-0. 3g phosphoric acid, the weighing bottle release 250mL beaker, add water, 100mL, was added 5 drops of 0.1% phenolphthalein indicator, with 0. 3mol / L hydrogen The sodium oxide standard solution is titrated until the solution is reddish.

Wherein the mass fraction of ωH ₃ POa-phosphoric acid, %;
The concentration of the substance of the c(NaOH) sodium hydroxide standard solution, mol/L;
V consumption of sodium hydroxide standard solution volume, mL;
M-sample quality, g;
The molar mass of 0.098 phosphoric acid, kg/mol.

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