Pupil sheet · Acids, bases and indicators

What acids and bases do — questions

Name ______________________ Date ____________

Try every question before you use a nudge. Write in full sentences where you are asked to explain.

1. state / describe

A piece of zinc is dropped into dilute hydrochloric acid, and bubbles of gas form. Fill in the gaps. zinc + hydrochloric acid → zinc (1) ___ + (2) ___. To test the gas, hold a (3) ___ splint at the mouth of the tube: the gas burns with a (4) ___.

(1)

(2)

(3)

(4)

Nudge (only if you are stuck): An acid and a metal give a salt and a gas. Which part of the acid's name goes into the salt's name?

2. identify

Copper(II) carbonate, a green powder, is added to dilute nitric acid. It fizzes and dissolves to give a blue solution. Which row names the gas, its test and the result correctly?

Row	Gas	Test	Result
A	hydrogen	lighted splint	squeaky pop
B	carbon dioxide	bubble through limewater	limewater turns milky
C	oxygen	glowing splint	splint relights
D	carbon dioxide	lighted splint	squeaky pop

Circle one answer.

Nudge (only if you are stuck): Every carbonate and acid gives the same gas.

3. identify

Nickel(II) oxide and iron(III) hydroxide do not dissolve in water. Lithium hydroxide dissolves. Sodium nitrate is a salt. Match each substance to what it is.

Write the number of the matching option.

not a base
a base, not an alkali
an alkali

1. Nickel(II) oxide: ______
2. Iron(III) hydroxide: ______
3. Lithium hydroxide: ______
4. Sodium nitrate: ______

Nudge (only if you are stuck): A base is a metal oxide or hydroxide. An alkali is a base that dissolves in water.

4. construct

Potassium carbonate solution reacts with hydrochloric acid to give potassium chloride, water and carbon dioxide. Balance the equation.

Write a number in front of each formula. Leave it blank for 1.

____ K₂CO₃(aq) + ____ HCl(aq) → ____ KCl(aq) + ____ H₂O(l) + ____ CO₂(g)

Nudge (only if you are stuck): Start with potassium: K₂CO₃ has two potassium atoms.

5. name / give / explain

A pupil warms a white solid, ammonium nitrate, with calcium hydroxide powder in a test tube, and a sharp-smelling gas comes off. (a) Name the gas. (b) Give the word equation for the reaction. (c) The pupil holds damp red litmus paper at the mouth of the tube. Predict what happens, and explain.

(a) The gas

(b) Word equation

Nudge (only if you are stuck): Calcium hydroxide is a base, and ammonium nitrate is an ammonium salt.

6. give / identify

Barium hydroxide solution, an alkali, is neutralised by hydrochloric acid: barium hydroxide + hydrochloric acid → barium chloride + water. (a) Give the ionic equation for the neutralisation, with state symbols. (b) Identify the two ions that are in the solution before and after and do not change.

(a) Ionic equation

(b) The ions that do not change

Nudge (only if you are stuck): An acid in water gives H⁺ ions; an alkali gives OH⁻ ions. Which ions stay dissolved, unchanged?

7. predict

Exactly 20 cm³ of potassium hydroxide solution neutralises 20 cm³ of dilute nitric acid. A pupil adds the potassium hydroxide solution to 20 cm³ of the acid a little at a time. Which row gives the pH correctly?

Row	pH with 10 cm³ added	pH with 20 cm³ added	pH with 30 cm³ added
A	above 7	7	below 7
B	below 7	7	above 7
C	below 7	7	7
D	7	7	above 7

Circle one answer.

Nudge (only if you are stuck): Before 20 cm³, some acid is left over. After 20 cm³, which is left over?

8. explain / give

An indigestion tablet contains aluminium hydroxide, which does not dissolve in water, and magnesium carbonate. Stomach juice contains hydrochloric acid. (a) Explain why aluminium hydroxide is a base but not an alkali. (b) Give the word equation for the reaction of magnesium carbonate with hydrochloric acid. (c) Suggest why some people burp after taking the tablet.

(a) Base but not alkali

(b) Word equation

Nudge (only if you are stuck): A base is a metal oxide or hydroxide. What gas does a carbonate give with an acid?