2f - Acid, Alkaline and Titration

Question 1

What colour does litmus indicator solution turn in acidic, alkaline and neutral solutions?

Answer 1

Litmus indicator solution turns Red in Acidic solutions, Blue in Alkaline solutions, and Purple in Neutral solutions

Question 2

What colour does red litmus turn in acidic, alkaline and neutral solutions?

Answer 2

CIDIC SOLUTION: Stays Red
NEUTRAL SOLUTION: Stays Red
ALKALINE SOLUTION: Turns Blue

Question 3

What colour does blue litmus turn in acidic, alkaline and neutral solutions?

Answer 3

ACIDIC SOLUTION: Turns Red
NEUTRAL SOLUTION: Stays Blue
ALKALINE SOLUTION: Stays Blue

Question 4

When does Phenolphthalein change colour? Where is it used?

Answer 4

Phenolphthalein changes colour sharply at approximately pH 8, and is commonly used in titrations

Question 5

What is Methyl Orange?

Answer 5

Methyl Orange is a solution and changes into a range of warm colours

Question 6

What colour does phenolphthalein change to in acid, neutral and alkali solutuions?

Answer 6

ACID SOLUTION - colourless
NEUTRAL SOLUTION - colourless
ALKALI SOLUTION - pink

Question 6

What colour does methyl orange change to in acid, neutral and alkali solutuions?

Answer 6

ACID - red
NEUTRAL - yellow
ALKALI - yellow

Question 7

What is a universal indicator?

Answer 7

Solution or paper indicator that changes into a range of colours to specifically identify pH of solution

Question 8

What do the different numbers on the pH scale mean?

Answer 8

The pH scale ranges from 0 to 14, and tells you how acidic or how alkaline a solution is.
strongly acidic: 0-3
weakly acidic: 4-6
neutral: 7
weakly alkaline: 8-10
strongly alkaline: 11-14

Question 9

What is the universal indicator?

Answer 9

If using universal indicator solution, a few drops of this indicator solution is added to the Aqueous Solution and colour change is observed and matched to specific colour on pH scale (to identify pH)

If using universal indicator paper, this paper is dipped into Aqueous Solution and colour change is observed and matched to specific colour on pH Scale (to identify pH)

Question 10

What happens when Acids dissolve in Water to form an Aqueous Solution?

Answer 10

they produce Hydrogen ions (H+) which makes the Aqueous Solution Acidic

Example: Hydrochloric Acid
HCl (aq) → H+ (aq) + Cl- (aq)

*Acids are often produced from Non-Metal Oxides, E.g Sulfur Oxides produce Sulfuric Acid

Question 11

What happens when Alkalis dissolve in Water to form an Aqueous Solution?

Answer 11

they produce Hydroxide ions ( OH- ) which makes the Aqueous Solution an Alkali

Example: Sodium Hydroxide
NaOH (aq) → Na+ (aq) + OH- (aq)

Question 12

What is neutralisation?

Answer 12

Reaction which removes Acidity or Alkalinity of solution

Question 13

Can alkali/acids neutralise each other?

Answer 13

When Alkali is added to an Acid, the pH of mixture rises as the Alkali reacts with Acid to form a neutral solution

When an Acid is added to an Alkali, the pH of the mixture falls as the Acid reacts with Alkali to form a Neutral Solution

Question 14

What does a neutralisation reaction involving an acid and base produce? give the equation:

Answer 14

Neutralisation reaction involving an Acid and base (Alkali) will always produce a Salt and Water:

Acid + Base (Alkali) → Salt + Water

When H+ ions from an Acid reacts with the OH- ions from an Alkali, this forms Water, causing the neutral solution to be formed:

H+ (aq) + OH- (aq) → H2O (l)

Question 15

What are some examples of bases?

Answer 15

Metal oxides, metal hydroxides and ammonia (NH₃) are called bases.

Question 16

What does this neutralisation produce
H₂SO₄ + CuO –> ???

Answer 16

H₂SO₄ + CuO → CuSO₄ + H₂O