Litmus solution

Request or contribute your recipes here. You can also try doing a search, as there are some old recipe posts which have not or cannot be moved over to this forum.
Post Reply
Catie
Posts: 4
Joined: 05 Feb 2018, 12:38
State/Location: NSW

Litmus solution

Post by Catie »

Hi Everyone
I am having trouble making Litmus Solution. I have tried 2 recipes. One says to add 10g of Litmus, boil then filter. The filtering takes a long time.
The other says to add 5g and stand for 24hrs then add 2 drops of Sodium Hydroxide. After I make the solution it is a nice purple colour but after it sits for a couple of days it turns a reddish brown colour. Can anyone help?
User avatar
Labbie
Posts: 3011
Joined: 28 Nov 2006, 10:00
Job Title: Retired
Suburb: At Home
State/Location: NSW

Re: Litmus solution

Post by Labbie »

Litmus Boil 5g in a litre of water. Stand, Filter
Aways worked will for us
Regards Labbie

Lab Manager/Lab Tech, mind reading etc etc
Now retired :wub:
Marama T
Posts: 85
Joined: 01 Aug 2017, 12:19
Job Title: Laboratory technician
School: Emmanuel Anglican College
Suburb: Ballina
State/Location: NSW

Re: Litmus solution

Post by Marama T »

I'd try posting this question on Science Assist for Teresa Gigengack.
User avatar
DavidPeterson
Posts: 196
Joined: 02 Apr 2012, 12:19
Job Title: STEM Resource & Lab Manager
School: Murray Bridge High School
Suburb: Murray Bridge
State/Location: SA

Re: Litmus solution

Post by DavidPeterson »

If it's turning red over time, possibly the solution is absorbing CO2 increasing the overall acidity. Make sure it's stored in a sealed bottle.
If this is what is happening, then a bit more NaOH to elevate the pH will return it to blue.
DCP 8-)
STEM Resource @ Laboratory Manager
RPAS (Drone) Pilot
Post Reply