This document defines bases and alkalis and discusses their properties. Bases are substances that accept hydrogen ions, while alkalis are soluble bases that release hydroxide ions in water and have a pH greater than 7. Alkalis have a bitter taste, turn litmus paper blue, are caustic, and conduct electricity in solution. They can undergo neutralization reactions with acids and precipitation reactions with metal salts to form insoluble metal hydroxides.

1. bases&alkalis
GROUP MEMBERS:
CELINE, JIAN YUE, EUGENE, RACHEL

2. what are Bases?
a base is a substance that can
accept hydrogen ions (H +)

3. what are Alkalis?
 Basic, ionic salt
 alkali metal or alkaline earth metal element.
 a base that dissolves in water.
 A solution of a soluble base has a pH greater than 7.
 A soluble base is referred to as an alkali if it contains and
releases hydroxide ions (OH−).

4. physical properties of alkalis
1. Alkalis have a BITTER taste & have a SOAPY touch
2. Alkalis turn RED litmus paper BLUE
3. Alkalis have a pH value > 7
4. Alkalis are CAUSTIC
5. Alkalis CONDUCT ELECTRICITY due to the presence
of MOBILE IONS in solution

5. chemical properties of alkalis
 Neutralization Reaction (Dilute Acid + Alkali –>
Salt + Water)
 Alkalireact with Ammonium Salts to
produce Ammonia Gas when heated gently
Alkali + Ammonium Salt –> Salt + Ammonia Gas
+ Water [Heat gently]

6. chemical properties of alkalis
 Precipitation of Insoluble Metal
Hydroxides from aqueous solutions
containing salts using common alkalis
such as NaOH & NH4OH
Metal Ions in Solution + Alkali –>
Insoluble Metal Hydroxide
(PRECIPITATES)

7. chemical properties of alkalis
E.g. :
Sodium Hydroxide + Iron (II) Sulphate
---
Iron (II) Hydroxide + Sodium Sulphate.

8. acknowledgements
 Presentation Created by Jian Yue.
 Research by Rachel
 Thanks to all sources that helped this presentation come true.
 We apologize for any accidental, unconditional copyrights. If there
is any clarifications, please kindly approach us.
 Software used to build this: Microsoft Powerpoint 2013 Preview.

9. Definition : Caustic
the property of a
substance that
causes corrosion