April 11, 2021, 06:06:52 AM
Forum Rules: Read This Before Posting


Topic: chemical test(not indicators) for acidic aqueous solution  (Read 4799 times)

0 Members and 1 Guest are viewing this topic.

annelise

  • Guest
chemical test(not indicators) for acidic aqueous solution
« on: December 05, 2004, 08:28:42 AM »
I have been set this question:

MHSO4 (where M stands for either Na or K) is a crystalline solid that dissolves in water giving a solution containing M+, HSO4-, H+ and SO42- ions.

Describe a chemical test (apart from indicators) by which you could demonstrate that an aqueous solution of MHSO4 is acidic.

So far I got that 1 test could be to test for CO2 by bubbling it through limewater (i.e. CO2 turns limewater milky in appearance), and I have this equation involving for that reaction:

CO2 (g) + Ca(OH)2 (aq) ---- CaCO3 (s) + H2O(l)

and the ionic half equation for testing for CO2 involving the H+ ions from the acid salt is:

2H+ (aq) + CO3- (s) ----H2O (l) + CO2 (g)

BUT I DON'T UNDERSTAND WHERE YOU SAY THE CARBON COMES INTO IT ALL? IS IT JUST FROM THE ATMOSPHERE? I AM CONFUSED ABOUT HOW TO WRITE THE EQUATION SAYING IS MHSO4 IS DISSOLVED IN WATER IT PRODUCES M+, HSO4-, H+ AND SO4(2-) IONS AND THEN INCORPORATING THE WHOLE C02 THING!

IM GETTING TOTALLY CONFUSED!

Offline Donaldson Tan

  • Editor, New Asia Republic
  • Retired Staff
  • Sr. Member
  • *
  • Posts: 3178
  • Mole Snacks: +261/-13
  • Gender: Male
    • New Asia Republic
Re:chemical test(not indicators) for acidic aqueous solution
« Reply #1 on: December 05, 2004, 11:44:38 AM »
you need a test to show the presence of hydrogen ions in the solution. addition of solid carbonate. eg. magnesium carbonate, will yield carbon dioxide gas, if H+ is indeed present.

calcium carbonate not good for use, because the insoluble calcium sulphate formed will coat the unreacted calcium carbonate and thus prevent furthur effervescence of carbon dioxide gas. In situation whereby [H+] is low, you may not observe effervescence because so little carbonate has reacted due to formation of the coat.
"Say you're in a [chemical] plant and there's a snake on the floor. What are you going to do? Call a consultant? Get a meeting together to talk about which color is the snake? Employees should do one thing: walk over there and you step on the friggin� snake." - Jean-Pierre Garnier, CEO of Glaxosmithkline, June 2006

Offline Mitch

  • General Chemist
  • Administrator
  • Sr. Member
  • *
  • Posts: 5296
  • Mole Snacks: +376/-3
  • Gender: Male
  • "I bring you peace." -Mr. Burns
    • Chemistry Blog
Re:chemical test(not indicators) for acidic aqueous solution
« Reply #2 on: December 05, 2004, 03:10:01 PM »
ph meter  ;)
Most Common Suggestions I Make on the Forums.
1. Start by writing a balanced chemical equation.
2. Don't confuse thermodynamic stability with chemical reactivity.
3. Forum Supports LaTex

annelise

  • Guest
Re:chemical test(not indicators) for acidic aqueous solution
« Reply #3 on: December 06, 2004, 10:46:59 AM »
ok cool! Thank you!!!!!  ;D

Sponsored Links