Free Reactions of Group I Elements MCQs with Answers
68 Reactions of Group I Elements MCQs from Chemistry, each with the correct answer and a written explanation of why it is correct. Free and unlimited, with no account needed.
Group I elements have one valence electron, so their reactivity increases down the group as ionisation energy decreases. Their reactions with water, oxygen, hydrogen and halogens produce hydroxides, oxides, hydrides and halides, while the behaviour of lithium differs from the heavier metals because of its small ionic size.
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- A. Sodium carbonate
- B. Sodium bicarbonate
- C. Sodium metal
- D. Sodium hydroxide
Explanation: The Downs cell electrolyses molten sodium chloride to produce sodium metal at the cathode and chlorine gas at the anode.
Correct answer: Sodium metal- A. Low electronegativity
- B. Low electropositivity
- C. Low charge density
- D. Not known yet
Explanation: Lithium ion has a small size and high charge density, so it strongly polarizes the carbonate ion and makes Li2CO3 less stable on heating…
Correct answer: Low electropositivity- A. small size
- B. high charge density
- C. less electropositivity
- D. all of the above
Explanation: Lithium differs from the other alkali metals because its atom and ion are unusually small, giving Li+ a high charge density; it is also…
Correct answer: all of the above- A. NaNO3
- B. CaCO3
- C. Ba (NO3)2
- D. NH4Cl
Explanation: Chile saltpetre is the mineral name for sodium nitrate, NaNO3, a naturally occurring nitrate deposit from Chile.
Correct answer: NaNO3- A. Their oxides are basic
- B. Their oxide and hydroxides are water soluble
- C. Both A & B
- D. They are found in earth
Explanation: Group 1 metals are called alkali metals because their oxides and hydroxides produce soluble alkaline solutions in water.
Correct answer: Both A & B- A. Hard water
- B. Heavy water
- C. Soft water
- D. Water gas
Explanation: Deuterium is the heavy isotope of hydrogen, so its oxide is D2O, commonly called heavy water.
Correct answer: Heavy water- A. form starch sugar and fibrous material
- B. ripen the seeds and fruits
- C. increase the resistance against disease
- D. all the above statements are correct
Explanation: Potassium activates enzymes and improves several plant processes, including starch and sugar formation, seed and fruit development, and…
Correct answer: all the above statements are correct- A. Na K
- B. Mg Ca
- C. Li Na
- D. Li Ca
Explanation: Lithium nitrate decomposes to lithium oxide, whereas sodium nitrate decomposes to sodium nitrite: 4LiNO3 -> 2Li2O + 4NO2 + O2 and 2NaNO3…
Correct answer: Li Na- A. Li is less electropositive
- B. Li has low ionization potential
- C. Li+ can effectively polarize CO3-2 ion
- D. Li+ cannot effectively polarize CO3-2 ion
Explanation: The thermal instability of lithium carbonate (Li2CO3) compared to other alkali metal carbonates due to following reasons:Size and Charge…
Correct answer: Li+ can effectively polarize CO3-2 ion- A. Basic oxides
- B. Acidic oxides
- C. Amphoteric oxides
- D. Both B and C
Explanation: Alkali metals are basic. The oxides they form are also basic due to this.
Correct answer: Basic oxides- A. Li+
- B. Na+
- C. K+
- D. Cs+
Explanation: When considering the heat of hydration, the size and charge density of cations play a crucial role.
Correct answer: Cs+- A. Positive
- B. Negative
- C. Zero
- D. All
Explanation: The heat of solution refers to the heat change when a solute dissolves in a solvent.
Correct answer: Negative- A. Low electronegativity
- B. High charge density
- C. Low charge density
- D. Not known yet
Explanation: Lithium ion (Li⁺) is very small with a high charge density. This high charge density polarizes the carbonate ion (CO₃²⁻) strongly, making…
Correct answer: High charge density- A. Rubidium
- B. Potassium
- C. Sodium
- D. Cesium
Explanation: Options A, B and D are incorrect as Na is the uppermost element in alkali metals and down the group, electropositive character or metallic…
Correct answer: Sodium- A. NH4+
- B. K+
- C. Mg2+
- D. Al3+
Explanation: b) K+ (potassium ion):The potassium ion (K+) produces a characteristic lilac or violet flame color during a flame test.
Correct answer: K+- A. Element sodium can be prepared and isolated by electrolyzing an aqueous solution of NaCl
- B. Elemental Na is a strong oxidizing agent
- C. Elemental Na is insoluble in NH3
- D. Elemental Na is easily oxidizing
Explanation: Good reducing agents include the active metals, such as sodium, magnesium, aluminum, and zinc, which have relatively small ionization…
Correct answer: Elemental Na is easily oxidizing- A. Low electronegativity
- B. Low melting point
- C. Their ions are isoelectronic with noble gas
- D. High ionization energy
Explanation: Alkali metals have low ionization energies due to their larger atomic radii.
Correct answer: High ionization energy- A. Electron affinity
- B. Reactivity
- C. Ionisation energy
- D. All of the above options are correct
Explanation: The reactivity of Group I elements increases as you go down the group because: the atoms get larger as you go down the group.
Correct answer: Reactivity- A. Ionization energy
- B. Reactivity
- C. Electron affinity
- D. Electronegativity
Explanation: The reactivity of alkali metals increases as you go down the group because: the atoms get larger as you go down the group.
Correct answer: Reactivity- A. NaCl
- B. NaOH
- C. NaBr
- D. ClO
Explanation: Option A: When molten sodium (Na) comes into contact with chlorine (Cl₂) gas, a vigorous reaction takes place, resulting in the formation…
Correct answer: NaCl