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Simple volumetric analysis question

Submitted by Anonymous (not verified) on Tue, 03/11/2008 - 07:32

Okay i'm gonna throw it out there. These are the question i can't do. Some of them r probably really easy but my textbook has no explanation

1. The concentration of sodium hyroxide in waste water from an alumina refinery was found by titrating 20ml aliquots of waste water agaisint .15M hydrochloric acid, using phenolphthalein as indciator. The average titre of several titration was 11.4ml. What mass of sodium hydroxide would be present in 100L of the waste water?

2. A 1.20 g anatacid tablet contains 80.% by mass of magnesium hyroxide as the acitve ingredient. What volume of .15M hydrochloric acid could the anatacid tablet neutralise?

3 What volumes of .1M sulfuric acid woould be requires to neutralise a solution containing .5g of sodium hydroxide and .8g of potassum hydroxide?

4. A certain brand of washing soda contains partially hydrated sodium carbonate solid. A .3g sample completely reacts with 20ml of .250M hydrochloric acid. Calculate the percentage by mass of sodium carbonate in the washing soda.

thanks a heapzzzzzzzzzzzzzzzzzzz


The concentration of sodium hyroxide in waste water from an alumina refinery was found by titrating 20ml aliquots of waste water agaisint .15M hydrochloric acid, using phenolphthalein as indciator. The average titre of several titration was 11.4ml. What mass of sodium hydroxide would be present in 100L of the waste water?

to get teh mass of NaOH you first will have to get the moles

1 mole of HCl = 1mole of NaOH in the neutralization reaction

you used 11.4 ml of HCl

0.114 L x  .15 mol / L HCl = 0.0171 mol HCl

therefor

0.0171 mole HCl = 0.0171 mole NaOH

convert to grams by multiplying my molar mass of NaOH