Acids, alkalis and salts

Question 1

What colour will litmus paper turn in an acidic, alkaline and neutral solution?

Answer 1

Red in acidic, purple in neutral and blue in alkaline

Question 2

What colour will phenolphthalein turn in acidic and alkaline solutions?

Answer 2

Colourless in acidic and bright pink in alkaline

Question 3

What colour will methyl orange turn in acidic and alkaline solutions?

Answer 3

Red in acidic and yellow in alkaline

Question 4

What is an acid?

Answer 4

An acid is a source of hydrogen ions. They are proton donors.

Question 5

What is an base/alkali?

Answer 5

A base/alkali is a proton acceptor and a source of hydroxide ions.

Question 6

What can neutralise an acid?

Answer 6

An alkali/base

Question 7

What is the equation for an reaction with an acid and a base?

Answer 7

Acid + base –> salt + water

Question 8

Acid + metal oxide –>

Answer 8

Salt + water

Question 9

Acid + metal hydroxide –> Salt + water

Answer 9

Salt + water

Question 10

Acid + ammonia –>

Answer 10

Ammonium salt

Question 11

Acid + metal carbonate –>

Answer 11

Salt + water + carbon dioxide

Question 12

Are common salts of sodium potassium and ammonium soluble or insoluble?

Answer 12

Soluble

Question 13

Are nitrates soluble or insoluble?

Answer 13

Soluble

Question 14

Are common chlorides soluble or insoluble?

Answer 14

Soluble, except for silver chloride and lead chloride

Question 15

Are common sulphates soluble or insoluble?

Answer 15

Soluble, except for lead, barium and calcium sulphate

Question 16

Are common carbonates soluble or insoluble?

Answer 16

Insoluble, except for sodium, potassiumm and ammonium

Question 17

Are common hydroxides soluble or insoluble?

Answer 17

Insoluble, except for sodium, potassium and calcium

Question 18

How do you make an insoluble salt?

Answer 18

React two soluble salts together to get an insoluble salt.

Question 19

How to make an soluble salt?

Answer 19

1) React an acid that contains one of the ions that you want in the salt with an insoluble base that contains the other ion
2) Heat the acid in a water bath
3) Add the base to the acid and this will form an soluble salt
4) Filter off the excess solid to get a solution with only the salt and the water
5) Heat the solution to evaporate some of the water. Leave the solution to cool and allow the salt to crystallise. Filter off the solid salt and leave to dry

Question 20

How do you carry out an titration?

Answer 20

1) Using a pipette and a pipette filler add 25cm3 of an alkali to a conical flask along with 2 or 3 drops of indicator
2) Fill a burette with the acid
3) Using the burette add the acid to the alkali slowly while swirling .
4) The indicator will change colour when all the alkali has been neutralised.
5) Record the volume of acid and repeat the test