A clause is a group of words that functions as one part of speech, containing both a subject and a verb, and expresses a complete or incomplete thought. It can be used as a part of a sentence.
There are two main types of clauses:
Independent/Main Clause: A clause that can stand alone as a complete, meaningful sentence.
Example: Honesty is the best policy.
Subordinate/Dependent Clause: A clause that cannot stand alone and does not express a complete thought. It usually begins with a subordinating conjunction.
Example: If you do your work on time.
The subordinate clause is further divided into the following types:
Noun Clause
Adjective Clause
Adverb Clause
The Main or Independent Clause An independent clause can stand alone as a sentence and expresses a complete thought. Example: She loves to read books.
A dependent clause cannot stand alone and requires an independent clause to make sense. It begins with a subordinating conjunction.
Example: Because it was raining (incomplete thought without an independent clause).
Noun Clause
A noun clause functions as a noun in a sentence. It can act as the subject, object, or complement in a sentence.
Example:
1. What you did was wrong. (Noun clause as the subject)
2. I didn’t understand what he said. (Noun clause as the object)
3. The fact that she lied upset me. (Noun clause as the complement)
The Difference Between Noun and Noun Clause
A noun is a single word that acts as a subject, object, or complement. A noun clause is a group of words that functions as a noun.
Example:
Pepperoni is fine with me. (Noun as the subject)
Whatever you want is fine with me. (Noun clause as the subject)
Adjective Clause
An adjective clause contains both a subject and a verb, and it modifies a noun or pronoun. It usually begins with relative pronouns such as who, whom, whose, that, or which.
Example:
The man who is wearing a hat is my uncle.
In this sentence, who is wearing a hat is an adjective clause modifying man.
The Difference Between Adjectives and Adjective Clauses
An adjective is a single word used to describe a noun, while an adjective clause is a group of words that modifies a noun or pronoun.
Example:
The angry tiger snarled at me. (Adjective describing tiger)
The tiger that was angry snarled at me. (Adjective clause modifying tiger)
Adverb Clause
An adverbial clause, or adverb clause, is a group of words that functions as an adverb, modifying a verb, adjective, or another adverb. It often answers questions like when, where, how, and why.
Example: She sings louder than I do. (Adverbial clause: than I do modifies the verb sings)
The Difference Between Adverbs and Adverbial Clauses
An adverb is a single word that modifies verbs, adjectives, or other adverbs. An adverbial clause is a group of words that functions like an adverb to modify a verb, adjective, or clause.
Example:
He sings well. (Adverb modifying the verb sings)
He sings better than anyone else. (Adverbial clause modifying the verb sings)
This covers the main concepts and differences between types of clauses.
Sentence using a noun clause:
What she said at the meeting was very surprising.
Sentence using an independent clause:
I went to the store.
Sentence using an adjective clause:
The book that I borrowed from the library is amazing.
Sentence using a dependent clause:
Although it was raining, we went for a walk.
True or False:
Dependent clause is also called main clause. False
(A dependent clause cannot stand alone as a complete sentence, while a main or independent clause can.)
Answer The Following Question.
1. Why should a magnesium ribbon be cleaned before burning in air?
Ans: Magnesium is a highly reactive metal that quickly forms a thin, stable layer of magnesium oxide when exposed to oxygen in the air. This oxide layer prevents further reaction of magnesium with oxygen. To ensure proper combustion, the magnesium ribbon is cleaned with sandpaper to remove this oxide layer, exposing the pure magnesium underneath for efficient burning.
2. Write the balanced equation for the following chemical reactions.
(i) Hydrogen + Chlorine → Hydrogen chloride
(ii) Barium chloride + Aluminium sulphate → Barium sulphate + Aluminium chloride
(iii) Sodium + Water → Sodium hydroxide + Hydrogen
Ans :
(i) H2+Cl2⟶2HCl
(ii) 3BaCl2 + Al2(SO4)3 → 3BaSO4 + 2A∣Cl3
(iii) 2Na +2H2O ⟶ 2NaOH + H2↑.
3. Write a balanced chemical equation with state symbols for the following reactions.
(i) Solutions of barium chloride and sodium sulphate in water react to give insoluble barium sulphate and the solution of sodium chloride.
(ii) Sodium hydroxide solution (in water) reacts with hydrochloric acid solution (in water) to produce sodium chloride solution and water.
Ans :
(i) BaCl2(aq) + Na2SO4 (aq) → BaSO4 (s) + 2NaCl (aq)
(ii) NaOH (aq) + HCl (aq) → NaCl (aq) + H2O(l)
4. A solution of a substance ‘X’ is used for whitewashing.
(i) Name the substance ‘X’ and write its formula.
(ii) Write the reaction of the substance ‘X’ named in (i) above with water.
Ans:
(i) The substance ‘X’ is calcium oxide. Its chemical formula is CaO.
(ii) Calcium oxide reacts vigorously with water to form calcium hydroxide (slaked lime).
CaO(s)+H2O(l) ⟶ Ca(OH)2(aq)
5. Why is the amount of gas collected in one of the test tubes in Activity 1.7 double of the amount collected in the other? Name this gas.
In the electrolysis of water, the gas collected in double the amount is hydrogen. This is because water (H₂O) is composed of 2 parts hydrogen and 1 part oxygen by volume. During electrolysis, water splits into hydrogen and oxygen gases in this same ratio, resulting in twice the amount of hydrogen gas being collected compared to oxygen. 2H2O(l) → 2H2(g) + O2(g)
6. Why does the colour of copper sulphate solution change when an iron nail is dipped in it?
When an iron nail is dipped into copper sulphate solution, a chemical reaction occurs where iron displaces copper from the solution. This happens because iron is more reactive than copper. As a result, iron sulphate, which is green in colour, is formed, and copper is deposited. This causes the blue colour of copper sulphate solution to change to green. Fe(s) + CuSO4 (aq) ⟶ FeSO4(aq) + Cu(s)
7. Give an example of a double displacement reaction other than the one given in Activity 1.10.
Sodium carbonate reacts with calcium chloride to form calcium carbonate and sodium chloride.
Na2CO3(aq) + CaCl2(aq) ⟶ CaCO3(s) + 2NaCl(aq)
8. Identify the substances that are oxidised and the substances that are reduced in the following reactions.
(i) 4Na+O2→ 2Na2O
(ii) CuO+H2→ Cu(s)+H2O
Ans:
(i) Sodium (Na) is oxidised as it gains oxygen and oxygen gets reduced.
(ii) Copper oxide (CuO) is reduced to copper (Cu) while hydrogen(H2) gets oxidised to waterH2O
9. Which of the statements about the reaction below are incorrect?
2PbO(s) + C(s) →2Pb(s) + CO2(g)
(a) Lead is getting reduced.
(b) Carbon dioxide is getting oxidised.
(c) Carbon is getting oxidised.
(d) Lead oxide is getting reduced
(i) (a) and (b)
(ii) (a) and (c)
(iii) (a), (b) and (c)
(iv) all
Ans : As statement (a) and (b) are incorrect, answer (i) is correct.