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Litmus Paper (Getty Images)
You can make paper test strips to determine the pH of an aqueous solution by treating filter paper with any of the common pH indicators. One of the first indicators used for this purpose was litmus. Litmus paper is paper that has been treated with a specific indicator - a mixture of 10-15 natural dyes obtained from lichens (mainly Roccella tinctoria) that turns red in response to acidic conditions (pH < 7) and blue under alkaline conditions (pH > 7). When the pH is neutral (pH = 7) then the dye is purple. The first known use of litmus was around 1300 AD by Spanish alchemist Arnaldus de Villa Nova.

Litmus paper is handy as a general acid-base indicator, but you can get much more specific results if you use an indicator that has a more narrow test range or that offers a wider color range. Red cabbage juice, for example, changes color in response to pH all the way from red (pH = 2) through blue at neutral pH to greenish-yellow at pH = 12, plus you are more likely to find cabbage at the local grocery store than lichen.

Comments

February 20, 2009 at 10:54 pm
(1) apple says:

How to make a litmus paper from gumamela (flower)extracts?
Thanks!

September 9, 2009 at 6:44 am
(2) Kashyap says:

How to prepare litmus paper from simple filter paper?

October 20, 2009 at 7:41 am
(3) cyril says:

where is the answer to there questions?
i very! , most! , needest! it

April 26, 2011 at 5:19 am
(4) idont have name says:

whatever u solve it!

October 20, 2009 at 7:49 am
(5) Genesis Cabalteja says:

Very good… site…
it helps me a lot…

for my assignments…

hahah

November 19, 2009 at 3:33 am
(6) Valerie says:

This site has really come through for me the lst couple of weeks! It’s good to know there’s at least one solid homework guide and study aid out there!

November 7, 2011 at 9:44 am
(7) shadow says:

i know and whats shakin bakin

November 30, 2009 at 6:28 am
(8) kuldeep waidya says:

thank you.
this is very helpfull site
because it helps to build our base in chemistry

February 1, 2010 at 5:08 am
(9) richa says:

how does it change its color in different conditions

March 14, 2010 at 8:53 am
(10) lauter says:

can’t base change red litmus to pink

March 18, 2010 at 3:58 pm
(11) Was lauter supposed to be laughter??? says:

heyy x

Sooooooooo stuck on a assignment we have to do for Chem.

HELP!!!

March 25, 2010 at 2:08 pm
(12) mahathi says:

why does litmus paper change its colour in acidic and basic conditions?

March 29, 2010 at 7:39 am
(13) malcolm benn says:

how do u make litmus paper from simple filter paper

March 30, 2010 at 11:21 am
(14) Dave Bermani says:

What is the derivation of the actual word “litmus”? Every source on the web describes what it does, etc., but nothing else. Thanks.

April 6, 2010 at 12:58 pm
(15) lil tim says:

read this i had this science project there was a activity to do we had to put subsances together and put litmus paper in it and observe the reactions can you tell me how can be done so the next time i can do it and do it properly i still did not get it can you please tell me i ma really intrested it seams fun to do not really fun but you know science is fun

April 21, 2010 at 1:49 pm
(16) prajakta kuchik says:

can the used litmus paper after drying can be used for testing other solution?

June 20, 2010 at 1:55 am
(17) Abu Sayeed says:

Thanks Anne Marie . After 30 years of my studying chemistry I had to refresh my knowledge about litmus paper and pH test. I took the help of Ms. Anne through her blog.I am great full to her.
Thakns again for your endevours in blog.
Abu Sayeed,Dhaka, Bangladesh, South Asia

August 30, 2010 at 8:26 am
(18) Christina says:

Nice article. If you interested in ph strips why not try our site at Litmus Papers

October 9, 2010 at 1:43 am
(19) TERENCE says:

How is red litmus paper coloured(made) red and blue litmus paper coloured(made) blue before the ph test is undertaken for acidic and basic medium? How does the colour change take place in the acidic and basic medium later?
I am anxious to get a quick reply please.
With regards,
Terence
09-10-10

May 20, 2011 at 1:42 am
(20) jayant says:

change in colour of litmus in basic medium and acidic medium

May 24, 2011 at 8:29 am
(21) ivy says:

How is red litmus paper coloured(made) red and blue litmus paper coloured(made) blue before the ph test is undertaken for acidic and basic medium? How does the colour change take place in the acidic and basic medium later?
I am anxious to get a quick reply please.

June 21, 2011 at 1:48 pm
(22) Ellen says:

Is litmus paper poisonous or caustic? My cat is very sick and I am suspecting it ate one of these litmus papers for my chlorine pool. Would anybody happy to know? Please help!

July 17, 2011 at 3:15 am
(23) namesake says:

u shouid have some more points

September 9, 2011 at 8:25 am
(24) Jeot says:

Pls tell me what can be used instead of litmus paper….????

September 24, 2011 at 3:21 am
(25) R.Hariharan says:

Information given in this site is not clear. Exact information of making litmus paper or solution is not given !

October 23, 2011 at 4:53 pm
(26) Ali says:

What about Red litmus paper? or blue litmus paper?
what are the scales for those? Please reply ASAP I need it for a lab report, thanks

March 31, 2012 at 12:50 pm
(27) mubarak dayyabu says:

so much intresting to have this so that we can solve our problem here

July 16, 2012 at 8:50 am
(28) alliah says:

what are the materials in making a litmus paer and the procedure

July 20, 2012 at 1:57 am
(29) bhea says:

firstprepared an indicator then pour the indicator inceramic container cover itthe filter paper or bond paper with the indicator solution by deeping the paper in the indicator solution.air dry for five minutes. repeat the

to be contienu

August 13, 2012 at 3:40 am
(30) john chester says:

what is litmus paper in chemistry

November 11, 2012 at 7:16 am
(31) tamra Jones says:

Is there a definition for litmus??

November 29, 2012 at 10:27 pm
(32) taylorswift13 says:

Hey, I think this was really beneficial! Thanks a bunch!

February 20, 2013 at 6:18 am
(33) Sairam valluri says:

Good explanation. I would like to ask that how can we prepare it?

May 14, 2014 at 8:57 am
(34) Happiness E. says:

What is the mathematical representation of ph?

May 14, 2014 at 2:58 pm
(35) Anton says:

lol not sure :P

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