So, this was the main \"story\" before all the questions. Concentrated Sodium Hy

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So, this was the main "story" before all the questions.

Concentrated Sodium Hydroxide;
This is the saturated solution of solid Na OH pellets dissolved in water. Add 100 g of NaOH to 100 ml of water warmed to about 50°C. Mix until the NaOH is dissolved and allow to stand covered (to protect from C02 from the air) for a few hours or overnight. The carbonate will settle out and the supernatant can be removed by decanting or centrifuging. The concentration of the concentrated sodium hydroxide solution will be approximately 17 mol/L. It can be diluted to any desired concentration and the molarity established by titration against standard potassium hydrogen phthalate. Store in a plastic bottle.

Please let me know what is really needed for this question. I feel that the questions are written poorly and I'm having hard time figuring out.

1.05M AMP buffer reagent is prepared for an enzyme assay for the determination of alkaline phosphatase (ALP) activity according to the following directions: To 200 mL of 1.05M magnesium acetate in a 2L volumetric flask, weigh out and add 187.12 g of AMP (2 - 1amlno-2methyl - 1propanol, MW 89.14), add 200 mL of deionized water and dissolve. (AMP is a syrupy liquid at room temperature.) Add 27.56 mL of concentrated HCI (12M). While mixing, adjust pH to 10.66 plusminus 0.05 at 25 degree C. Dilute to 2L with water. Stable @ room temperature for one year. Before the AMP is added to the flask, it is measured and found to have a volume of 248.36 mL. When the pH of the reagent is checked before diluting to the final volume, it is found to be 10.56, which is not satisfactory. Two 50 mL aliquots of the reagent are removed from the flask without loss of reagent, put in small beakers, and duplicate titrations are carefully performed using a pH meter. The pH electrode is immersed in a 50 mL aliquot while the solution in the beaker is being stirred with a magnetic mixer. 1M NaOH is added slowly from an adjustable micro pipettor, while keeping track of the amount added, until the desired pH is reached. An average of 0.58m/50 mL aliquot is required to reach a satisfactory pH of 10.65 in the duplicate titrations. The 2 aliquots are then returned to the flask. How much 1M NaOH should be added to the reagent in the flask to adjust the pH to the desired level? How much more water will it take to fill the flask to the 2L mark? (Round off answers to the nearest 0.01 mL.)

Explanation / Answer

For reaching desired Ph of 10.65 we need 0.53ml of 1M NaOH is required in 50ml.

so let us calculate 1M NaOH required in 2000ml

0.53ml/50=x/2000ml

X=0.53 x 2000/50

=23.2ml of NaOH require

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