1. Define
an acid?
An acid is a substance which gives H+ ion or hydronium ion , H3O+ in water, (when it disassociate) e.g HCl, H2SO4
An acid is a substance which gives H+ ion or hydronium ion , H3O+ in water, (when it disassociate) e.g HCl, H2SO4
2. Define
a base.
A base is a substance which givesOH-
ion in water , ( when it disassociate) – NaOH, KOH etc.
A base is a substance which gives
3.
Name some natural indicators and some synthetic
indicators.
Natural indicator: Litmus, turmeric, red cabbage leaves, Petunia, Geranium, Hydrangea etc
Natural indicator: Litmus, turmeric, red cabbage leaves, Petunia, Geranium, Hydrangea etc
Synthetic
indicator: Methyl orange, phenolphthalein etc.
4. What
are olfactory indicators?
These are the substances which have different smell (odour) in acidic and basic medium. Olfactory indicators can be used in the laboratory to test whether a solution is a base or an acid, a process called olfactory titration. Onion, clove oil and vanilla extract are examples.
These are the substances which have different smell (odour) in acidic and basic medium. Olfactory indicators can be used in the laboratory to test whether a solution is a base or an acid, a process called olfactory titration. Onion, clove oil and vanilla extract are examples.
5. Why
does an aqueous solution of an acid conduct electricity?
When an acid is dissolved in water, ions become free to move and hence they can conduct electricity.
When an acid is dissolved in water, ions become free to move and hence they can conduct electricity.
6. What
is "water of crystallisation"?
The fixed number of water
molecules present in one formula unit of a crystalline salt is called water of
crystallisation, example : CuSO4.5H2O
7. What
is the pH of human blood ?
Human blood is slightly alkaline
with a pH in the range of 7.2 to 7.4.
8. What
do you understand by dilution of an acid or base?
Dilution of an acid or base means
mixing an acid or base with water to decrease the concentrations of ions (H+ in
acids or OH- in
bases) per unit volume.
9. What
is Soda ash ?
Soda ash is anhydrous sodium carbonate
(Anhydrous - Without water molecule. Its formula is Na2CO3.
10. What are
antacids?
Antacids are weak bases which
neutralise the excess acid in the stomach. Example of antacid is milk of
magnesia (Mg(OH)2). .
11. What
is the chemical name of washing soda ?
The chemical
name of washing soda is sodium carbonate decahydrateNa2CO3.10H2O.
Sodium carbonate decahydrate is a hydrated form of soda ash, a common raw material used in numerous industrial processes. Also called washing soda, the compound is used to remove stubborn laundry stains today.
Sodium carbonate decahydrate is a hydrated form of soda ash, a common raw material used in numerous industrial processes. Also called washing soda, the compound is used to remove stubborn laundry stains today.
12. Fresh milk
has a pH of 6.How do you think the pH will change as it becomes sour? Explain
your answer.
pH will decrease as the milk
becomes sour .It is because sour milk contains lactic acid.
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