All Free Chemistry MCQs with Answers

• A. Castings
• B. Hammer
• C. Tubes
• D. All of above

Explanation: Medium carbon steel is often used for castings because it provides good strength and hardness, making it suitable for components that need…

• A. Sulphates
• B. Dichromates
• C. Nitrates
• D. Chromates

Explanation: Dichromates, specifically potassium dichromate (K2Cr2O7), are powerful oxidizing agents.

• A. Sc3+
• B. Tc+
• C. Cu+
• D. Zn2+

Explanation: Technetium in its +1 oxidation state would have a definite value of magnetic moment due to its unpaired electron(s), while all other…

• A. Na
• B. Mg
• C. Fe
• D. Al

Explanation: Iron exhibits multiple oxidation states, including +2 (ferrous) and +3 (ferric).

• A. An acidic medium
• B. A basic medium
• C. A neutral medium
• D. It does not exist

Explanation: The equilibrium ( text{Cr}_2text{O}_7{2-} leftrightarrow 2text{CrO}_4{2-}) involves the chromate (text{CrO}_4{2-}) and dichromate (…

• A. Pig iron
• B. Steel
• C. Wrought iron
• D. Cast iron

Explanation: Steel is produced by refining pig iron in a Bessemer converter or other similar processes.

• A. 1
• B. 2
• C. 4
• D. 5

Explanation: The ferrous ion, Fe²⁺, has the electron configuration [Ar]3d⁶. In the 3d subshell, there are 4 unpaired electrons.

• A. Zn
• B. Sn
• C. Ni
• D. Any of the above

Explanation: This option indicates that all of the listed elements-zinc, tin, and nickel-can be used to coat iron surfaces for the purpose of…

• A. Transition elements have low melting points
• B. Transition elements do not have catalytic activity
• C. Transition elements exhibit variable oxidation states
• D. Transition elements exhibit inert pair effect

Explanation: Transition elements exhibit variable oxidation states: This statement is correct.

• A. 10
• B. 14
• C. 28
• D. 30

Explanation: This is the correct option because inner transition elements are those elements that have their outermost electrons in the f orbitals.

• A. 5
• B. 4
• C. 3
• D. 2

Explanation: A is correct because Mn2+ (Z=25) has a 3d5 electron configuration. In a d5 configuration, there are 5 electrons in the d orbital, and…

• A. 5
• B. 6
• C. 3
• D. 4

Explanation: When Fe loses three electrons to form Fe3+, it loses its 4s2 and one 3d electron, leaving behind five unpaired electrons in the 3d orbitals.

• A. CaSiO3
• B. FeSiO3
• C. MnSiO3
• D. All

Explanation: This option of all is correct because during the steelmaking process, various oxides such as CaO, FeO, MnO, SiO2, and others are present…

• A. 10
• B. 5
• C. 6
• D. 2

Explanation: The correct answer is option B, 5. This is because the balanced chemical equation for the reaction between acidified FeSO4 solution and…

• A. 24
• B. 23
• C. 22
• D. 21

Explanation: The element with atomic number 24 is chromium (Cr), which has an electronic configuration of (Ar) 3d5 4s1.

• A. Zn, Cd, Hg
• B. Fe, Fu, Os
• C. Cr, Mo, W
• D. Mn, Te, Re

Explanation: Chromium (Cr), molybdenum (Mo), and tungsten (W) belong to Group VI B of transition elements.

• A. Cr2OCl2
• B. CrO2Cl2
• C. Cr2OCl3
• D. CrOCl2

Explanation: This is the correct formula for chromyl chloride. It consists of one chromium atom, two oxygen atoms, and two chlorine atoms.

• A. Octahedral
• B. Square planar
• C. Tetrahedral
• D. Trigonal bipyramidal

Explanation: In PCl5, phosphorus pentachloride, the central phosphorus atom is surrounded by five chlorine atoms.

• A. I-A
• B. I-B
• C. II-A
• D. II-B

Explanation: The coinage metals, also known as Group 11 elements, consist of copper (Cu), silver (Ag), and gold (Au).

• A. sp
• B. dsp2
• C. spd2
• D. dsp3

Explanation: Phosphorus pentachloride (PCl5) has a dsp hybridization. In dsp hybridization, one s orbital, one d orbital, and three p orbitals are…