Dalton's Atomic Theory — NEET Chemistry MCQs with Solutions
Free NEET Chemistry Dalton's Atomic Theory MCQs with step-by-step solutions (7 questions). Part of Some Basic Concepts of Chemistry. Practise online on Prepizo — no login needed.
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Questions with solutions
Q1 — Dalton's Atomic Theory · easy · theory
In which year did John Dalton publish "A New System of Chemical Philosophy", in which he put forward his atomic theory?
A. 1808 ✓ Correct
B. 1803
C. 1789
D. 1811
Solution: John Dalton published "A New System of Chemical Philosophy" in 1808. The year 1803 is when he proposed the law of multiple proportions, 1789 is when Lavoisier stated the law of conservation of mass, and 1811 is when Avogadro proposed his law.
Q2 — Dalton's Atomic Theory · easy · theory
According to Dalton’s atomic theory, which statement about the atoms of a given element is correct?
A. All atoms of a given element are identical in mass and in all other properties ✓ Correct
B. Atoms of a given element can be broken down into smaller particles
C. Atoms of a given element differ from one another in mass
D. Atoms of a given element are identical to atoms of every other element
Solution: Dalton’s second postulate states that all atoms of a given element have identical properties, including identical mass, while atoms of different elements differ in mass. The other options describe ideas that came later — isotopes and subatomic particles — which Dalton’s original theory did not include.
Q3 — Dalton's Atomic Theory · easy · theory
According to Dalton, what happens to atoms during a chemical reaction?
A. Atoms of one element are converted into atoms of another element
B. New atoms are created from energy
C. Atoms of the reactants are destroyed
D. They are only rearranged; they are neither created nor destroyed ✓ Correct
Solution: Dalton’s fourth postulate states that a chemical reaction involves only the reorganisation (rearrangement) of atoms; atoms are neither created nor destroyed. This directly accounts for the law of conservation of mass.
Q4 — Dalton's Atomic Theory · medium · theory
Dalton’s postulate that "compounds are formed when atoms of different elements combine in a fixed ratio" provides the theoretical basis for which law?
A. Avogadro’s law
B. Law of definite proportions ✓ Correct
C. Gay Lussac’s law of gaseous volumes
D. Law of conservation of mass
Solution: If a compound always forms from atoms combining in a fixed ratio, it must always contain the same elements in the same proportion by mass — this is the law of definite (constant) proportions given by Proust. Conservation of mass follows from the rearrangement postulate, while the gaseous-volume and Avogadro laws are NOT explained by Dalton’s theory.
Q5 — Dalton's Atomic Theory · medium · theory
Dalton’s atomic theory was able to explain the laws of chemical combination, but it could NOT explain which of the following?
A. Law of multiple proportions
B. Gay Lussac’s law of gaseous volumes ✓ Correct
C. Law of definite proportions
D. Law of conservation of mass
Solution: As stated in the NCERT text, Dalton’s theory explained the laws of chemical combination (conservation of mass, definite proportions, multiple proportions) but could not explain the law of combining gaseous volumes (Gay Lussac’s law); it also gave no reason for why atoms combine.
Q6 — Dalton's Atomic Theory · easy · theory
The term "atom" comes from the Greek word "a-tomio". What does this word mean?
A. Invisible
B. Weightless
C. Indivisible ✓ Correct
D. Spherical
Solution: "A-tomio" means indivisible. The idea of matter being made of small indivisible particles dates back to the Greek philosopher Democritus (460–370 BC); Dalton later revived it on an experimental footing. Dalton’s assumption that atoms are indivisible was itself disproved later by the discovery of subatomic particles.
Q7 — Dalton's Atomic Theory · medium · numerical
Sulphur forms two oxides, SO₂ and SO₃. The masses of oxygen that combine with a fixed 32 g of sulphur in these two oxides are in the ratio: (S = 32, O = 16)
A. 2:3 ✓ Correct
B. 3:2
C. 1:2
D. 1:1
Solution: In SO₂, 32 g of sulphur combines with 2 × 16 = 32 g of oxygen; in SO₃, 32 g of sulphur combines with 3 × 16 = 48 g of oxygen. The ratio of oxygen masses is 32:48 = 2:3, a simple whole-number ratio — an illustration of Dalton’s law of multiple proportions. (1:2 is the ratio for CO and CO₂; 3:2 is the inverted value.)