All Free Chemistry MCQs with Answers
Every Chemistry question in the bank, across all chapters, each with the correct answer and a written explanation. Free and unlimited, with no account needed.
13,720 questions · page 534 of 686
- A. Fe2O3
- B. Fe3O4
- C. FeO
- D. Fe2O3.3H2O
Explanation: This is the correct chemical formula for hematite. Hematite is composed of iron (Fe) and oxygen (O) atoms in a 2:3 ratio, so the formula…
Correct answer: Fe2O3- A. 2
- B. 3
- C. 6
- D. 7
Explanation: Option a suggests that there are two types of ligands in the complex. In [PtCl(NO2)(NH3)4]-2, the ligands present are chloride (Cl-) and…
Correct answer: 2- A. Zinc
- B. Iron
- C. Scandium
- D. Copper
Explanation: Iron is paramagnetic because it has unpaired electrons in its d orbitals, which align with an external magnetic field, causing it to be…
Correct answer: Iron10664. The purest form of iron is:
- A. Wrought iron
- B. Pig iron
- C. Cast iron
- D. Steel
Explanation: Wrought iron contains very low carbon content (less than 0.08%) and is known for its fibrous structure, making it highly malleable and…
Correct answer: Wrought iron- A. Coordination number
- B. Coordination sphere
- C. Chelates
- D. None of these
Explanation: Option b is the correct answer. It refers to the central metal atom/ion along with its attached ligands in a coordination complex.
Correct answer: Coordination sphere10666. Mild steel contains carbon:
- A. 0.1 to 0.2%
- B. 0.2 to 0.7%
- C. 0.2 to 0.6%
- D. 0.1 to 0.6%
Explanation: Mild steel with a carbon content ranging from 0.1% to 0.2% is characterized by its relatively low carbon content, making it softer and…
Correct answer: 0.1 to 0.2%- A. 0.25 to 2.5%
- B. 0.12 to 0.20%
- C. 3.0 to 4.5%
- D. 2.0 to 4.5%
Explanation: This range represents the typical carbon content in carbon steel, which is the most common type of steel used in construction and…
Correct answer: 0.25 to 2.5%- A. O2
- B. O2+
- C. O2-
- D. O2-2
Explanation: O2 has two unpaired electrons. Each oxygen atom contributes one unpaired electron to form the O=O bond, resulting in two unpaired…
Correct answer: O2- A. Zero
- B. Two
- C. Four
- D. Six
Explanation: Each copper ion in [Cu(NH3)4]SO4 is coordinated to four ammonia (NH3) ligands.
Correct answer: Four- A. p to d orbitals
- B. d to d orbitals
- C. p to p orbitals
- D. d to p orbitals
Explanation: The color of transition metal complexes is due to the transition of electrons between different energy levels within the d orbitals of the…
Correct answer: d to d orbitals- A. Parke's process
- B. Solvay process
- C. Cyanide process
- D. Amalgamation process
Explanation: The Parke's process is a pyrometallurgical industrial process for removing silver from lead during the production of bullion.
Correct answer: Parke's process- A. Cu
- B. Cu+
- C. Cu-
- D. Cu2+
Explanation: Electronic configuration of the options are as follows:Option A, Cu: 1s2 2s2 2p6 3s2 3p6 3d10 4s1, so its d subshell is filledOption B…
Correct answer: Cu2+- A. Para magnetism
- B. Diamagnetism
- C. Ferromagnetism
- D. Both Ferromagnetism and Paramagnetism
Explanation: It is useful, at the beginning, to identify the physical and chemical properties of transition elements which differ from main group…
Correct answer: Para magnetism- A. Blue
- B. Yellow
- C. Brown
- D. Pink
Explanation: The valence shell electronic configuration of Cu+2 ions is 3d9 Hence, aqueous Cu+2 ions are blue in colour,It contains 1 unpaired…
Correct answer: Blue- A. Cr3+
- B. Ti3+
- C. V3+
- D. Zn2+
Explanation: Electronic configuration of chromium 3+ is [Ar] 3d3. Cr3+ has 3 unpaired electrons in its outer most shell and thus it's the element which…
Correct answer: Cr3+- A. [Ar] 3d4 4s2
- B. [Ar] 3d2 4s2
- C. [Ar] 3d5 4s1
- D. [Ar] 3d5 4s2
Explanation: Chromium(Cr) and Copper(Cu) are two special cases in which electron from 4s orbital jumps to 3d so 4s orbital has only a single electron…
Correct answer: [Ar] 3d5 4s1- A. Cu
- B. Sc
- C. Zn
- D. Cr
Explanation: The answer to the question should be option C because Zinc does not show the variable valency as elements of the d-block.
Correct answer: Zn- A. Normal elements
- B. Transition elements
- C. Metallic elements
- D. None of them
Explanation: Transition elements show variable oxidation states because: 1. The energy difference between 3d and 4s orbitals is very small. 2.
Correct answer: Transition elements- A. [Co(en)3](NO3)3
- B. [Co(NH3)3(NO2)3]
- C. K3[Co(NO2)6]
- D. [Pt(NH3)2Cl4]
Explanation: Only option that has complex ion attached to cation is K3[Co(NO2)6], giving a definite evidence of it being anion. Hence it is the answer.
Correct answer: K3[Co(NO2)6]- A. Cr
- B. Co
- C. Fe
- D. Sn
Explanation: Right from the start, you can guess that the unknown element must be a d-block element, or a transition metal.
Correct answer: Cr