Few past HSC q's-NEED HELP PLZ :) (1 Viewer)

[Lingb]

hey..i have a few past hsc questions im just struggling a bit with. if anyone can give me some advice, feedback, or anythin, id greatly appreciate it
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Q1) which of the methods is qualitative....
method A: 25ml samples of water were titrated agaisnt EDTA with erichrome black T indicator. 21.7ml of EDTA was required. the hardness was calculated to be equivalent to 17mg/l of CaCO3
OR
method B:three drops of detergent were added to seperate vials containing 5ml samples of distilled water, hard water and the sample. after shaking the vials ten times, the heights of froth were compared. the procedure was repeated twice. as the amount of froth in the three samples was only slightly less than in the distilled water the sample was determined to be soft

im pretty sure it is method B, but yer, the whole qualitive and quantitve thing gets me.
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Q2) compare the appropriateness of Method A and method B (from above) for determing the hardness of the water
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Q3) identify 2 common indicators of water quality that would be most useful in monitoring waste water from a fruit cannery.justify your choices.


ANY HELP ON THESE 3 QUESTIONS WOULD BE GREATLY APPRECIATED!
THANKYOU WHOEVER COMES TO MY AID!

 

[Forbidden.]

Q1) I agree Method B. Quantitative deals with numbers while qualitative is based on "amount or degree"

Q2) Method A is much more accurate ?

Q3) Maybe some pH checks ? You don't want to affect aquatic life because citric acid and other acidic compounds were responsible for lowering the pH of water.

Some AAS as well could help, maybe, you don't want too much metals present in the water system (from cans which are made from iron and tin).

 

[Lingb]

thanx f3nr15.

ur answer to Q3, very good
now u said it, kinda a bit obvious, but the pH and the citric acid from the cannery, very good. i doubt i wud have thought of that. cheers

would u be able to elaborate on q2 by any chance?
like reasons for/against for A being more accurate over B?

cheers again, your help is greatly appreciated.
i shall sleep a lil easier tonight.