Acids, Bases, and pH

Dec 2011
7
0
1. What are acids and bases?
2. What is pH and how is it measured?
3. What happens when substances with different pH levels are combined?
4. What is the pH of different foods?



I would like as many of these questions answered as possible, with at least semi technical answers.. Id greatly appreciate it. :)
 
Dec 2011
22
0
Acids and bases

acids and bases have different definition in different Lewis , Arrhenius and Bronsted-Lowry , you can get their definition in my link.

This is what pH means : pH = - log [H+] , so you need to reach the H+ concentration first and calculate pH by the above formula. [H+]=M.
α.n (here α is the dissociation degree,M molarity of our acid , n how many acidic H+ does it have)

When substances with different pH levels are combined the pH changes. of course if we add a base pH goes up and if we add an acid it goes down.

 
Feb 2012
1
0
Los Angeles
PH, Acid And Basic

Hi PH Mean Polarity Of hydronium Ions For Any Particular substance. It may be -ve and +ve also

The pH scale measures how acidic or basic a substance is. The pH scale ranges from 0 to 14. A pH of 7 is neutral. A pH less than 7 is acidic. A pH greater than 7 is basic.

For distillate Water It's PH is 7.00 Mean It's Not In Acid and basic.
 
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Mar 2012
2
0
Acid, Base and PH

We acid and bases are fully different compound. Here,
Acid: Which gives H+ ion in aqueous solution that means acid is such compound which has changeable hydrogen.
We define below:
HCl = H+ +Cl-
Here,
HCl gives H+ ion and this proton take reaction with another base.
Such as: H+Cl- + Na+OH- = NaCl + H2O

Bases:
In another way, Bases gives OH- ion. The main reason of base called so is of appearing OH- group.

PH:
PH means effectiveness of acid or basic.
Follow here
PH>7= Base
PH<7= Acid



Law of calculating PH
PH = -log[H+]
Here, we calculating PH by knowing the concentration of H.

PH of different foods are different.
Here some acidic foods:

Corn
Meat
Beans
Fish
Fowl
Most grains
Coffee
Plums
Prunes
Cranberries
 
Apr 2012
1
0
Hi,

Hi,
Acids are ionic compounds ( a compound with a positive or negative charge) that break apart in water to form a hydrogen ion (H+).
The strength of an acid is based on the concentration of H+ ions in the solution. The more H+ the stronger the acid.
Example: HCl (Hydrochloric acid) in water

Bases are ionic compounds that break apart to form a negatively charged hydroxide ion (OH-) in water.
The strength of a base is determined by the concentration of Hydroxide ions (OH-). The greater the concentration of OH- ions the stronger the base.
Example: NaOH (Sodium Hydroxide-a strong base) in water.

The strength of an acid or base in a solution is measured on a scale called a pH scale.
**The pH scale is a measure of the hydrogen ion concentration. It spans from 0 to 14 with the middle point (pH 7) being neutral (neither acidic or basic).
Any pH number greater than 7 is considered a base and any pH number less than 7 is considered an acid. 0 is the strongest acid and 14 is the strongest base.

-----------------------------------
Debra Fine
 
Jan 2019
12
2
India
Concept of pH


The dissociation of water, Kw, has such low value that expressing the concentrations of H⁺ and OH⁻ ions of a solution in terms of such low figures is not much convenient and meaningful. Such expressions necessarily have to involve negative power of the base 10. Sorensen proposed the use of a term known as pH , defined as:
pH = - log[H+] = log(1/[H+])
 
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