SPM Chemistry Form 4 Notes – Acids and Bases (Part 3)

by BerryBerryTeacher

in Berry Reference (Notes)

If we are talking about opposites in chemistry, there can not be any more opposites than acid and alkali. Acids are the chemical opposites of bases. This is (partly) due to their where acids donates a hydrogen ion to another compound called base, hence they are chemically opposite. Of course there are other differences between the chemical properties of acids and bases. Thus, this Part 3 of notes for SPM Chemistry Form 4 on Acids and Bases from Berry Berry Easy will be on the comparison of chemical properties of acids and bases.

[Tips: Often, students try to memorise both sets of properties for acid and alkali. While this is the correct thing to do, but more often than not, certain properties are direct opposites that you only need to remember one half to recall the other. So do use this trick to memorise the differences.]

SPM Chemistry Form 4 Notes – Acids and Bases (Part 3)

Sodium hydroxide

Sodium hydroxide

Chemical Properties

Acid Alkali
In the presence of water, an acid will ionise to form hydrogen ion, H+. In the presence of water, an alkali will ionise to form hydroxide ion, OH -.
Sour in taste Bitter in taste
pH values less than 7 pH values more than 7
Indicator: Blue litmus paper (Red) Indicator: Red litmus paper (Blue)
Indicator: Universal indicator (Orange and red) Indicator: Universal indicator (Blue and purple)
Indicator: Methyl orange (Red) Indicator: Methyl orange (Yellow)
React with bases to produce salts and water.

2HCl(aq) + CuO(s) –> CuCl2(aq) + H2O(l)

React with acids to produce salts and water.

NaOH(aq) + HCl(aq) –> NaCl(aq) + H2O(l)

React with metals (reactive metal, higher position than H+ in the electrochemical series) to produce salts and hydrogen gas.

2HCl(aq) + Zn(s) –> ZnCl2(aq) + H2(g)

React with an ammonium salt (alkali is heated) to produce ammonia gas.

Ba(OH)2(aq) + 2NH4Cl(s) –> BaCl2(aq) + 2H2O(l) + 2NH3(g)

React with carbonates to produce salts, carbon dioxide gas and water.

H2SO4(aq) + ZnCO3(s) –> ZnSO4(aq) + H2O(l) + CO2(g)

React with aqueous salt solutions to produce metal hydroxides (as precipitate).

2NaOH(aq) + CuSO4(aq) –> Na2SO4(aq) + Cu(OH)2(s)

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This ends Part 3 of the notes for SPM Chemistry Form 4 on Acids and Bases from Berry Berry Easy. In the next part in the series, you’ll be exposed to the important definitions for acids including monoprotic and polyprotic acids. So do check back to our site for more essential notes.

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July 15, 2012

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