Lesson: Acids, Bases, and Salts
have been provided with three test tubes. One of them contains distilled water
and the other two contain an acidic solution and a basic solution,
respectively. If you are given only red litmus paper, how will you identify the
contents of each test tube?
The content of
the tube will be an acid if the colour of red litmus does not change when
dipped into it.
It is a base if
the colour of red litmus changes to blue.
If there is a slight
change in the colour of red litmus (purple), then it is distilled water.
should curd and sour substances not be kept in brass and copper vessels?
Curd and other
sour substances contain acids. Therefore, when they are kept in brass or copper
vessels, the metal reacts with the acid. This results in release hydrogen gas
and other harmful products. This spoils the food.
gas is usually liberated when an acid reacts with a metal? Illustrate with an
example. How will you test for the presence of this gas?
gas is usually liberated when an acid reacts with a metal.
few pieces of zinc granules in a test tube.
5 ml of dilute .
it and pass the gas produced through a soap solution.
Bubbles are formed in the soap solution
are formed. These soap bubbles contain hydrogen gas.
Now test if the evolved gas is hydrogen or not.
When a candle is brought near the
soap bubbles the gas burns with a pop sound.
This proves that the evolved gas is
compound A reacts with dilute hydrochloric acid to produce effervescence. The
gas evolved extinguishes a burning candle. Write a balanced chemical equation
for the reaction if one of the compounds formed is calcium chloride.
compound formed due to the reaction is calcium chloride. This means that the
metal compound has calcium metal. The gas that extinguishes
a burning candle is carbon dioxide. This means the metal compound is calcium
do , , etc., show acidic characters in
aqueous solutions while solutions of compounds like alcohol and glucose do not
show acidic character?
When or are mixed
with water, they dissolve in water to form hydrogen ion or hydronium
ion . Due to the presence of these ions, these
compounds show their acidic character.
When alcohol and
glucose are mixed with water, they do form hydrogen or hydronium ions. Hence,
they do not show acidic character.
does an aqueous solution of acid conduct electricity?
Acids ionises in aqueous solutions.These ions are
responsible for conducting electricity.
does dry gas not change the colour of the dry litmus
not show it acidic property unless it is dissolved in water. When dissolved in
water, they form or ions. Due to
these ions, these compounds show their acidic character. This ionization does
not happen in case of dry gas and
hence dry gas does not change the colour of the dry
diluting an acid, why is it recommended that the acid should be added to water
and not water to the acid?
The reaction of
acid and water is exothermic in nature. If water is added to an acid, the heat
generated can cause burns. To slow down the generation of heat, it is always
recommended that acid should be added to water.
is the concentration of hydronium ions ( )
affected when a solution of an acid is diluted?
water is added to a solution of acid, the solution becomes diluted.
concentration of hydronium ions ( )
decreases when a solution of an acid is diluted. This means that the strength
of the acid decreases.
is the concentration of hydroxide ions ( )
affected when excess base is dissolved in a solution of sodium hydroxide?
hydroxide is basic in nature. When excess base is dissolved in a solution of
sodium hydroxide, the concentration of hydroxide ions ( )
have two solutions, A and B. The pH of solution A is 6 and pH of solution B is
8. Which solution has more hydrogen ion concentration? Which of this is acidic
and which one is basic?
An acid has a
pH value less than 7 while a base has a pH value more than 7.
with is acidic
and has more hydrogen ion concentration than the basic solution.
effect does the concentration of (aq) ions have on the nature of the solution?
Concentration of (aq) can
have varied effects on the nature of the solution. If the concentration of ions
increases, the solution becomes more acidic. If the concentration of ions
decreases, the solution becomes more basic in nature.
Do basic solutions also have (aq)
ions? If yes, then why are these basic?
solutions also have (aq) ions.
They are basic despite having (aq)
solution. This is due to the presence of less concentration of (aq)
compared to the concentration of ions in the
what soil condition do you think a farmer would treat the soil of his fields
with quick lime (calcium oxide) or slaked lime (calcium hydroxide) or chalk
plant grows the best when the soil is neither acidic not basic. The farmer
would treat the soil with quick lime or slaked lime or chalk when the soil is
acidic in nature. Quick lime or slaked lime or chalk are basic in nature and neutralizes
the acidic nature of the soil when they are added to it.
is the common name of the compound ?
The common name
of the compound is
the substance which on treatment with chlorine yields bleaching powder.
the sodium compound which is used for softening hard water.
will happen if a solution of sodium hydro carbonate is heated?
the equation of the reaction involved.
When a solution of sodium hydro
carbonate is heated, sodium carbonate and water are formed. Carbon dioxide too is
released in this process.
an equation to show the reaction between Plaster of Paris and water.