Acids and Bases Quiz

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Questions and Answers

What color does copper sulfate turn after heating?

Green

Blue

Yellow

White (correct)

What happens when water is added to heated copper sulfate?

It turns red.

It turns blue again. (correct)

It remains white.

It dissolves completely.

How many water molecules are present in one formula unit of hydrated copper sulfate?

5 (correct)

What is the chemical formula for gypsum?

CaSO4.2H2O Signup and view all the answers

What is produced when gypsum is heated at 373 K?

Calcium sulfate hemihydrate Signup and view all the answers

What role does water of crystallization play in salts?

It affects the color of the crystals. Signup and view all the answers

Which of the following is NOT a characteristic of water of crystallization?

It can be absorbed from the air. Signup and view all the answers

What is Plaster of Paris used for?

Supporting fractured bones Signup and view all the answers

What color does blue litmus paper turn when placed in an acidic solution?

Red Signup and view all the answers

Which of the following substances is commonly used as a natural acid-base indicator?

Turmeric Signup and view all the answers

If a stain of curry on a cloth becomes reddish-brown when scrubbed with soap, what can you conclude about soap?

It is basic in nature Signup and view all the answers

What is the main reason baking soda solution is suggested for acidity relief?

It neutralizes acids Signup and view all the answers

What happens to red litmus paper when placed in a basic solution?

It turns blue Signup and view all the answers

What does litmus solution indicate when it is purple?

It is neutral Signup and view all the answers

Which of the following indicators changes color when it comes into contact with acids?

Methyl orange turns red Signup and view all the answers

Which of the following substances would likely not alleviate symptoms of acidity?

Lemon juice Signup and view all the answers

What is likely the pH of a solution that turns red litmus blue?

10 Signup and view all the answers

What gas is produced when a solution reacts with crushed egg-shells that turns lime-water milky?

Carbon dioxide Signup and view all the answers

If 10 mL of NaOH is neutralised by 8 mL of HCl, how much HCl is needed to neutralise 20 mL of NaOH?

16 mL Signup and view all the answers

Which type of medicine is used for treating indigestion?

Antacid Signup and view all the answers

Why do acids not exhibit acidic behavior in the absence of water?

They ionize when dissolved in water. Signup and view all the answers

Which of the following solutions is neutral based on their pH values?

pH 7 Signup and view all the answers

What characteristic allows distilled water to not conduct electricity?

It lacks minerals. Signup and view all the answers

Among solutions with pH values 4, 1, 11, 7, and 9, which is the weakly acidic solution?

pH 4 Signup and view all the answers

What is produced when sodium hydrogencarbonate is heated?

Sodium carbonate Signup and view all the answers

Why is sodium hydrogencarbonate effective in neutralizing an acid?

It is a non-corrosive base. Signup and view all the answers

What defines a strong acid compared to a weak acid?

Strong acids produce more H+ ions than weak acids. Signup and view all the answers

What reaction occurs when baking powder is mixed with water?

Carbon dioxide is produced. Signup and view all the answers

Which use is NOT associated with sodium hydrogencarbonate?

Glazing pottery Signup and view all the answers

Why is pH important for living organisms?

Living organisms can only survive in a specific pH range. Signup and view all the answers

What consequence does acid rain have on aquatic life?

It lowers the pH of rivers, making survival difficult for aquatic life. Signup and view all the answers

What do the 10H2O in Na2CO3.10H2O signify?

Number of water molecules combined Signup and view all the answers

How are the pH values of lemon juice and tap water likely to differ?

Lemon juice has a lower pH than tap water. Signup and view all the answers

Which industrial application is sodium carbonate known for?

Manufacturing of soap Signup and view all the answers

What primary role does sodium bicarbonate play in fire extinguishers?

Generates carbon dioxide to smother fires Signup and view all the answers

What pH range is considered acidic?

A pH less than 7. Signup and view all the answers

Which statement about washing soda is correct?

It is a basic salt. Signup and view all the answers

What factor does the strength of a base depend on?

The number of OH– ions produced. Signup and view all the answers

What is the primary component of Venus's atmosphere?

Sulphuric acid. Signup and view all the answers

What could be a pH measurement for saliva after a meal compared to before a meal?

after a meal is usually lower than before. Signup and view all the answers

Study Notes

Acids and Bases

Acids are sour and turn blue litmus red.
Bases are bitter, turn red litmus blue, and are also known as alkalis.
Turmeric is a natural indicator; it turns reddish-brown in the presence of a base and yellow in the presence of an acid.
Lemon juice, vinegar, and baking soda solutions are commonly used as remedies for acidity.
Baking soda (sodium hydrogencarbonate) is basic and neutralizes excess acid in the stomach.
Indicators are substances that change color in the presence of acids or bases.
Methyl orange and phenolphthalein are synthetic indicators.
The strength of an acid or base depends on the number of H+ or OH- ions produced, respectively.
Strong acids produce more H+ ions, while weak acids produce fewer H+ ions.
Strong bases produce more OH- ions, while weak bases produce fewer OH- ions.

pH Scale

The pH scale measures the acidity or basicity of a solution.
It ranges from 0 to 14.
pH 7 is neutral.
Values below 7 indicate acidity, while values above 7 indicate basicity.
Living organisms can only survive within a narrow pH range.

Acid Rain

Rainwater with a pH less than 5.6 is called acid rain.
It occurs when sulfur dioxide and nitrogen oxides released from burning fossil fuels react with water in the atmosphere.
Acid rain lowers the pH of rivers and lakes, posing a threat to aquatic life.

Salts

Salts are formed by the reaction of an acid and a base.
Salts are ionic compounds that are generally formed when the hydrogen ion of an acid is replaced by a metal ion.
Examples of salts include sodium chloride (NaCl), potassium chloride (KCl), and calcium carbonate (CaCO3).

Sodium Hydrogencarbonate (Baking Soda)

Sodium hydrogencarbonate (NaHCO3) is a mild, non-corrosive basic salt.
It decomposes upon heating, producing sodium carbonate, water, and carbon dioxide.
It is used in baking powder, antacids, and soda-acid fire extinguishers.

Sodium Carbonate (Washing Soda)

Sodium carbonate (Na2CO3) is a basic salt.
It is used in the glass, soap, and paper industries, as well as in the manufacture of sodium compounds like borax.
It can be used as a cleaning agent and for removing permanent hardness in water.

Water of Crystallisation

Water of crystallisation refers to the fixed number of water molecules present in one formula unit of a salt.
Copper sulfate (CuSO4.5H2O) contains five water molecules of crystallisation.
Gypsum (CaSO4.2H2O) contains two water molecules of crystallisation.

Plaster of Paris

Plaster of Paris is calcium sulfate hemihydrate (CaSO4.1/2H2O).
It is formed when gypsum (CaSO4.2H2O) is heated at 373K.
It is used as a plaster for supporting fractured bones.

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Description

Test your knowledge about acids and bases with this quiz. Explore important concepts such as pH scale, indicators, and the characteristics of acids and bases. Understand how common substances like lemon juice and baking soda interact in chemical reactions.