Explore topic-wise InterviewSolutions in .

Glucose and alcohol do not produce H⁺ ions when dissolved in water. The acids contain hydrogen. When acid is dissolved in water, produce H⁺ ion.

Weak acids: Acids that give fewer (less) H₃O⁺ ions (They are not ionized completely).

Action of metals 

Except for Cu, Ag and Au, Boron combines with other metals at high temperatures to form borides. These borides are extremely hard substances. Mg₃B₂ and Be₃B₂ are attacked by acids to form boron hydrides.

Action Of Non Metals

Boron also reacts with non-metals. For example: Boron combines with N₂ at temperatures greater than 900 C to form boron nitride, BN. Boron forms boron sulphide B₂S₃ when heated with S. On heating with Carbon in an electric furnace an extremely hard substance namely boron carbide, B4C is formed.

Action Of Steam

Boron reacts with steam at red heat liberating H₂. 

2B + 3H₂O → B₂O₃ + 3H₂

Acetic acid (CH₃COOH) is a monobasic acid, i.e. it contains only one replaceable hydrogen ion per molecule of the acid. As such it can only form normal salts.

Strong Alkali – Is an alkali which dissociates – almost completely in aqueous solution thereby producing a – high concentration of hydroxyl [OH^– ] ions.

NaOH [aq] ⇋ Na⁺ + OH^-

KOH [aq] ⇋ K⁺ + OH^-

[contains almost - only ions]

Examples: Lithium, Sodium and Potassium hydroxide

Weak alkali – Is an alkali which dissociates – only partially in aqueous solution thereby producing a – low concentration of hydroxyl [OH^–] ions.

NH₄OH [aq] ⇋ NH₄⁺ + OH^-

[contains - molecule and ions]

Examples: Ammonium hydroxide and Calcium hydroxide. 

(a) An alkali and a base:

1. Alkalis are soluble in water whereas bases may be or may not be soluble in water.

2. All alkalis are bases but all bases are not alkalis.

(b) An alkali and metal hydroxide :

1. Alkalis are soluble in water whereas metal hydroxides may be or may not be soluble in water

a. If in the place of zinc granules, same amount of zinc dust is taken in the test tube then the rate of the reaction will increase and the reaction will take place more quickly. This is because the surface area per unit volume of powder is more than that of the zinc granules and hence the powder will provide more surface area for the reaction to take place. 

b. If in place of dilute sulphuric acid, we use dilute hydrochloric acid then the reaction will take place as usual because in both the cases we are mixing a strong acid with a metal. 

c. If in place of zinc, copper turnings are taken then also the reaction will proceed in a similar way and would lead to the evolution of hydrogen gas as here we are only replacing one metal with another metal in the reactant side of the reaction. In this case, also we are mixing a strong acid with a metal. 

d. If sodium hydroxide is taken in place of dilute sulphuric acid and the tube is heated then the metal will react with the base to form the corresponding salt and will evolve hydrogen gas as per the following reaction:- 

Zn + 2NaOH → Na₂ZnO₂ + H₂

Exothermic reaction: A chemical reaction in which heat is evolved.

(i) Bulb A and B do not glow but bulb C glows.

(ii) Glucose and alcohol solutions do not conduct electricity as they do not have ions.-Dil. HCl Contains, ions so the flow of current.

(iii) After replacement, bulb glows in B as NaOH solution contains ions (Na⁺ and OH^- ions).

Mixing concentrated acids or bases with water is a highly exothermic process.

d) 16 ml HCl solution is required.

If we take double the amount of the NaOH solution, the amount of the HCI solution required to neutralise it is also double. Hence, the correct answer is (d).

Metallic oxides are basic, few are amphoteric.

Non-metallic oxides are acidic, few are neutral.

An alkali is a basic hydroxide which when dissolved in water produces hydroxyl ions (OH^-) as the only negatively charged ions.

(a) Strong alkalis: Sodium hydroxide , Potassium hydroxide

(b) Weak alkalis: Calcium hydroxide , Ammonium hydroxide

a. The common salt that we use in your food is obtained by the combination of base - sodium hydroxide (NaOH) and the acid - hydrochloric acid (HCl).

The formula for the common salt that we use in your food is NaCl and its name is sodium chloride. 

It is obtained from seawater. 

b. When the seas of bygone ages dried-up beds of rock salt were being formed. Rock salts are the deposits of solid salts. 

The colour of rock salt is brown. It is brown in colour due to the impurities present in it. 

c. When electricity is passed through brine it decomposes to form sodium hydroxide along with the evolution of chlorine gas at anode and hydrogen gas at cathode. Sodium hydroxide solution is also formed near the cathode. 

The chemical equation for the above decomposition is: - 

2NaCl (aq) +2H₂O (l) → 2NaOH (aq) + Cl₂ (g) + H₂ (g)

Acid solutions have ions and the electric current is carried through the movement of ions in the solution. 

In glucose and alcohol ions are absent.

Dissolving bases in water produces hydroxide (OH^- ) ions.

The process of dissolving an acid or a base in water is an exothermic process.

Two solid metals are :

(i) Copper (Cu)

(ii) Sodium (Na).

Two solid non-metals are :

(i) Iodine (I)

(ii) Silicon (Si)

(a) H⁺ ions of acid combine with OH^- ions of alkali to form water, H₂O.

(b) Temperature of the solution rises.

(c) Applying a coating of zinc
(We can also apply grease and paint to prevent iron from rusting. However, in case of iron frying pan, grease and paint cannot be applied because when the pan will be heated and washed again and again, the coating of grease and paint would get destroyed.)

Bases that are soluble in water are called alkalis.

We should not taste or touch alkali. Because they are corrosive.

Gangue: Ores mined from the earth are usually contaminated with large amounts of impurities such as soil, sand etc., called gangue.

1. a. Chlorine

2. b. Nacl

3. b. NO

4. b. Electrostatic

5. b. FALSE

(a) Hydrogen

(b) Hydrogen

 Neutralization reaction

1. b. Exposed to air

2. a. Corrosion

3. b. Making oxide layer thicker

4. a. Anodising

5. a. TRUE

1. d. Both A and B

2. a. Many materials are togetherly found

3. c. Both A and B

4. a. Earth

5. d. Mercury

They all produce hydroxide ions when dissolved in water.

Iron and aluminium will displace hydrogen from dilute acids as they are more reactive then hydrogen. Mercury and copper can not displace hydrogen from dilute acids as they are less reactive than hydrogen.

The common name of water soluble bases is-

Alkalis

The metals which are the least reactive, they are often found in a free state. For example: Gold, silver, platinum and copper are found in the free state.

In the electrolytic refining of a metal M:
Anode → Impure metal M
Cathode → Thin strip of pure metal M
Electrolyte → Solution of salt of the metal M

1. b. FALSE

2. a. Displacement

3. b. NO

4. b. All Metals do not react with reagents

5. d. All of the above

Zn matter does not displace H₂ gas from dilute HCl or H₂SO₄.

Answer: Acid

Alkali.

NaOH or KOH

The correct answer is (d) Bromine and mercury

An amphoteric compound is a molecule or ion that can react both as on acid as well as a base. Many metals such as Zinc, Tin, Lead, aluminum and can form amphoteric oxides or hydroxides. Two examples are Al₂O₃ and ZnO.

Metal with very low reactivity do not react with air. So they do not get rust. They also called as noble metals, e.g.: Gold, platinum.

Oxides which show both acidic and basic behaviour and oxides that react with both acids as well as bases to produce salts and water. 

Example: Al₂O₃ and ZnO.

A) High reactive metals can displace less reactive metals from its compound.

The correct answer is (c)  Alcohol

Rusting takes place on iron. The reason is iron react with air that contains oxygen and moisture forms a reddish brown coating (rust) due to formation of iron oxide.

Correct option is C) Chemical properties

(a) Those metal oxides which show basic as well as acidic behavior are known as amphoteric oxides.

Example: Aluminium oxide and zinc oxide.

(b) Acidic oxide – CO₂ , CO, SO₂ and N₂O; Basic oxide – Na₂O, MgO; Neutral oxide – H₂O.

(c) ZnO, Al₂O₃ .

Generally metallic oxides are basic in nature and non-metallic oxides are acidic in nature.

Correct option is  A) X: acidic, Y : basic

Metals are lustrous because they are shining in nature.