All Free Chemistry MCQs with Answers

• A. +4
• B. +2
• C. -1
• D. -4

Explanation: We know that the charge of Na is always +1, and the overall charge on the Na2C2 molecule is 0.

• A. Strong oxidizing agent
• B. Strong reducing agent
• C. Very weak oxidizing agent
• D. Very weak reducing agent

Explanation: The correct answer is that chromium compounds in which the oxidation state of chromium is 2+ behave as strong reducing agents.

• A. H2 + Cl2 --> 2HCl
• B. C2H4 + H2 --> C2H6
• C. 2Na + H2 --> 2NaH
• D. N2 + 3H2 --> 2NH3

Explanation: In the correct reaction, 2Na + H2 --> 2NaH, sodium (Na) is oxidized, as it loses electrons to form Na+, while hydrogen (H2) is reduced to…

• A. +1
• B. +5
• C. -1
• D. +3

Explanation: In the compound NCLO3, the oxidation state of Cl (chlorine) is indeed +5.

• A. Oxygen
• B. Fluorine
• C. chlorine
• D. Both (A) & (C)

Explanation: Fluorine has a consistent oxidation number of -1 in all of its compounds because it is the most electronegative element and always gains…

• A. Mn+4
• B. Mn-1
• C. Mn+6
• D. All of the above

Explanation: So, an oxidizing agent is a substance that causes other substances to lose electrons, resulting in oxidation.

• A. Cl2
• B. F2
• C. Br2
• D. I2

Explanation: A reducing agent is a substance that causes another substance to be reduced in a chemical reaction.

• A. Of normal binary hydride
• B. Of an interstilial hydride
• C. of covalent hydride
• D. That does not exist

Explanation: HYDRIDES Hydrogen compounds with metals and non-metals are known as hydrides.

• A. Aluminium can be recycled
• B. Aluminium is light
• C. Aluminium is cheaper
• D. Aluminium is resistant to corrosion

Explanation: It is because aluminium is resistant to corrosion by organic acids.

• A. 13,22
• B. 3,11
• C. 4,24
• D. 2,4

Explanation: Option B is correct as the elements with atomic numbers 3 and 11 are Lithium and sodium, respectively which are both in the same group…

• A. HOCl
• B. HCIO2
• C. HClO3
• D. HClO4

Explanation: The oxidizing power of oxy acids of halogens increases as the oxidation number of the halogen in the compound increases.

• A. Xe is the most reactive among rare gasses
• B. He is an inert gas
• C. Randon is obtained from decay of radium
• D. The most abundant rare gas found in atmosphere is He

Explanation: The most abundant rare gas found in the atmosphere is Argon not Helium.

• A. 13,22
• B. 3,11
• C. 4,24
• D. 2,4

Explanation: Elements belonging to the same group have the same chemical properties.

• A. F
• B. Cl
• C. Br
• D. I

Explanation: Fluorine is unique among the halogens as it is the most electronegative element, and it only forms compounds where it can achieve a -1…

• A. 1
• B. 2
• C. 3
• D. 4

Explanation: The most electronegative elements are found in Period 2 of the periodic table.

• A. H-I
• B. H-O
• C. H-S
• D. H-Cl

Explanation: The correct option is C: H-S. The bond length between hydrogen and sulfur is longer due to the relatively lower electronegativity of…

• A. Metals
• B. Non metal
• C. Metalloid
• D. None of the above

Explanation: Arsenic and Antimony are classified as metalloids. Metalloids are elements that have properties of both metals and nonmetals.

• A. Al
• B. Si
• C. Fe
• D. P

Explanation: Phosphorus being more electronegative than Si forms more acidic oxides.

• A. 35.50
• B. 34.50
• C. 72.00
• D. 70.00

Explanation: The atomic mass of Cl35 is approximately 35.00 atomic mass units (amu), and the atomic mass of Cl37 is approximately 37.00 amu.

• A. Na2O
• B. MgO
• C. Al2O3
• D. P2O5

Explanation: Sodium oxide is highly basic because it readily releases hydroxide ions when dissolved in water, resulting in a highly alkaline solution.