On this day

On 8th January 1868, Søren Peder Lauritz Sørensen was born in Havrebjerg, Denmark.  He died on 12th February 1939.  He was a Danish chemist famous for the introduction of the concept of pH, a scale for measuring acidity and basicity.

From 1901 to 1938 he was head of the prestigious Carlsberg Laboratory, Copenhagen. While working there he studied the effect of ion concentration on proteins, and because the concentration of hydrogen ions was particularly important, he introduced the pH-scale as a simple way of expressing it in 1909.

The article in which he introduced the scale (using the notation pH), described two new methods for measuring acidity. The first method was based on electrodes, while the second involved comparing the colours of samples and a preselected set of indicators.

pH is a measure of the acidity or basicity of an aqueous solution. Solutions with a pH less than 7 are said to be acidic and solutions with a pH greater than 7 are basic or alkaline. Pure water has a pH very close to 7.

For more information visit:-

http://en.wikipedia.org/wiki/PH

http://www.encyclopedia.com/topic/Soren_Peter_Lauritz_Sorensen.aspx

Back to school

Where did the summertime break go?  Time for kids to go back to school.  And time for us too...chemistry basics.....Acids and bases

All acids:

• have a low pH (1-6) – the lower the number the stronger the acid
• react with bases to form neutral compounds
• are corrosive when they are strong
• are an irritant when they are weak.

Acids have a pH of less than 7. Bases have a pH of more than 7. When bases are dissolved in water, they are known as alkalis. Salts are made when an acid reacts with a base, carbonate or metal. The name of the salt formed depends on the metal in the base and the acid used. For example, salts made using hydrochloric acid are called chlorides.

Acids
Substances with a pH of less than 7 are acids. The more strongly acidic the solution, the lower its pH number. Acidic solutions turn blue litmus paper red. They turn universal indicator paper red if they are strongly acidic, and orange or yellow if they are weakly acidic.

Bases
Substances that can react with acids and neutralise them to make a salt and water are called bases. They are usually metal oxides or metal hydroxides. For example, copper oxide and sodium hydroxide are bases.

Alkalis
Bases that dissolve in water are called alkalis. Copper oxide is not an alkali because it does not dissolve in water. Sodium hydroxide is an alkali because it does dissolve in water.

Alkaline solutions have a pH of more than 7. The stronger the alkali, the higher the pH number. Alkalis turn red litmus paper blue. They turn universal indicator paper dark blue or purple if they are strongly alkaline, and blue-green if they are weakly alkaline.

Neutral solutions
Neutral solutions have a pH of 7. They do not change the colour of litmus paper, but they turn universal indicator paper green. Water is neutral.

For pH meters or pH test papers or buffer solutions give us a call.

For more information visit:-
http://www.prlabs.co.uk
http://en.wikipedia.org/wiki/PH