Download presentation
Presentation is loading. Please wait.
1
Properties of Acids and Bases
Ionization Neutralization reactions Acid/base indicators
2
What is ionization? Acids dissolve in water to produce , hydrogen ions (H+) and other ions. when dissolved in water. These ions are surrounded by water molecules. This is called ionization.
3
Bases dissolve in water to yield hydroxide ions (OH-) and other ions.
For example, sodium hydroxide ionizes into hydroxide ions and sodium ions.
4
Strong and Weak Acids & Bases
Strong acids ionize 100% in water: HCl, HNO3, HClO4, H2SO4 Weak acids ionize less than 100% in water. Common examples: H3PO4, HCH3COO, H2CO3 Whether an acid is strong or weak depends on the amount of hydrogen ionized. Soluble metal hydroxides ionize 100% and are strong bases NaOH, KOH, Mg(OH)2 Others are weak bases NH3(aq) + H2O(l) NH4+(aq) + OH-(aq)
5
Neutralization Reactions
What would happen if an acid and a base were mixed up? What would happen if a hydrogen ion (H+) from an acid reacted with a hydroxide ion (OH-) from a base?
6
a strong acid and a strong base solution are mixed, a neutralization reaction occurs .
The products are a salt and water . This acid-base reaction is called a neutralization reaction.
7
Neutralization - reaction of an acid and base forming a salt and water.
HCl + NaOH NaCl + HOH Salts - composed of the positive half of a base and the negative half of an acid. Question: What acid and base react to produce each of these salts? CaSO4 NH4NO3 CaCl2
8
Acid-Base Indicators Certain chemicals have the special property of appearing in different colours depending on the pH of the solution they are in. Such chemicals are known as acid-base indicators A couple of drops of indicator in a solution will indicate its pH.
9
Three commonly used indicators.
11
congo red phenolphthalein phenol red thymol blue methyl green methyl orange bromthymol blue
14
What household substances can be used as acid/base indicators?
· Beets change from red to purplish in very basic solution. · Blackberries, black currants, and black raspberries change from red in acids to dark blue or violet in basic solution. · Blue and red grapes contain several different pH-sensitive anthocyanins. Red wines naturally contain these same pigments. · Blueberries change from blue (around pH ) to red in a strongly acidic solution. · Carrots · Cherries and cherry juice is bright red in acidic solution but purple to blue in basic solution. · Cranberries · Curry powder and tumeric are spices that contain a bright yellow pigment called curcumin (which is not an anthocyanin). It turns from yellow at pH 7.4 to red at pH 8.6. · Geranium petals contain pelargonin, an anthocyanin which changes from orange-red in acid solution to bluish in basic solution. · Mood lipsticks undergo many interesting pH-related color changes. · Morning glories contain an anthocyanin called "heavenly blue anthocyanin" which changes from purplish red at pH 6.6 to blue at pH 7.7. · Pansy petals · Petunia petals contain petunin, an anthocyanin that changes from reddish purple in acid to violet in basic solution. · Poppy flower petals · Red cabbage contains a mixture of anthocyanins and other pigments that indicate a wide range of pH. · Red radish · Rhubarb · Rose petals contain the oxonium salt of cyanin, and they turn blue in basic solution. (The potassium or calcium salt of the same pigment makes cornflowers blue!) · Strawberries · Tea · Thyme (extract in alcohol) · Tulip petals · Vanilla extract, like onion, is an olfactory indicator. The vanilla odor isn't detectable in strongly basic solution because vanillin exists in ionic form at high pH. · Violet petals
Similar presentations
© 2025 SlidePlayer.com. Inc.
All rights reserved.