PH

PH 

 1. What is PH?

2.What are PH values?

Do these values depend on something?  Explain your answers.

3. Check Chart 3.2 about acids and bases.

4. What is Neutralization?  Give examples.What can you explain about it?

  

ANSWERS

1.In chemistry, pH (/piːˈ(h)eɪtʃ/) (potential of hydrogen) is a numeric scale used to specify the acidity or basicity of an aqueous solution. It is approximately the negative of the base 10 logarithm of the molar concentration, measured in units of moles per liter, of hydrogen ions. More precisely it is the negative of the logarithm to base 10 of the activity of the hydrogen ion.^[1] Solutions with a pH less than 7 are acidic and solutions with a pH greater than 7 are basic. Pure water is neutral, at pH 7 (25°C), being neither an acid nor a base. Contrary to popular belief, the pH value can be less than 0 or greater than 14 for very strong acids and bases respectively.^[2]

2. The pH scale is theoretically open-ended but most pH values are in the range from 0 to 14.An acid is a substance that donates hydrogen ions. A base is a substance that accepts hydrogen ions. The acid solutions have lower PH values. The basic solutions have higher PH values.

3. 
All acids and bases do not ionize or dissociate to the same extent. This leads to the statement that acids and bases are not all of equal strength in producing H+ and OH- ions in solution. The terms "strong" and "weak" give an indication of the strength of an acid or base. The terms strong and weak describe the ability of acid and base solutions to conduct electricity. If the acid or base conducts electricity strongly, it is a strong acid or base. If the acid or base conducts electricity weakly, it is a weak acid or base.

4.In chemistry, neutralization is a chemical reaction in which an acid and a base react quantitatively with each other. In a reaction in water, neutralization results in there being no excess of hydrogen or hydroxide ions present in the solution. The pH of the neutralized solution depends on the acid strength of the reactants. Neutralization is used in many applications.In the context of a chemical reaction the term neutralization is used for a reaction between an acid and a [alkaline (chemistry)|base]] or alkali. Historically, this reaction was represented as

acid + base → salt + water

For example:

HCl + NaOH → NaCl + H₂O