Principles Related to Practical Chemistry — NEET Chemistry video lectures, notes & PYQs

3 previous-year questions from this chapter every option and the correct answer, free · where the marks are

1. Detection of functional groups and elements

Exam focus: The iodoform test isn't exclusive to methyl ketones — any compound with a CH₃–CH(OH)– group, such as ethanol or isopropanol, also gives it, because it oxidises to the methyl ketone or aldehyde in situ under the test conditions. A positive iodoform test on an unknown alcohol therefore doesn't by itself prove a ketone is present — that's the standard trap.

Practical Organic Chemistry: Qualitative Analysis

Competition Wallah

Full-chapter practical organic chemistry video whose first half is qualitative analysis/detection of elements (Lassaigne's test, N/S/halogen/P tests); also includes purification and chromatography beyond this named subtopic.

2. Titrimetric analysis and salt analysis

Exam focus: Indicator choice depends on where the equivalence point's pH actually falls: phenolphthalein suits weak acid–strong base titrations (equivalence point is basic), methyl orange suits strong acid–weak base (equivalence point is acidic), and either works for strong acid–strong base. Reaching for phenolphthalein out of habit on a strong-acid–weak-base titration — where the colour change happens well past the actual equivalence point — is exactly the error this tests.

Salt Analysis — Full Chapter

Competition Wallah

Thorough coverage of qualitative salt analysis (anion/cation tests) but does NOT cover titrimetric/volumetric analysis — no suitable combined or dedicated titrimetric-analysis video from a reputable NEET channel could be verified, so only the salt-analysis half of this subtopic is covered.

ChemistryNEET 2025show ▾

Match List I with List II.

List I (Ion)	List II (Group number in cation analysis)
A. $C o^{2 +}$	I. Group I
B. $M g^{2 +}$	II. Group III
C. $P b^{2 +}$	III. Group IV
D. $A l^{3 +}$	IV. Group VI

Choose the correct answer from the options given below:

A.A-III, B-IV, C-II, D-I
B.A-III, B-IV, C-I, D-II✓
C.A-III, B-II, C-IV, D-I
D.A-III, B-II, C-I, D-IV

Solution

$P b^{2 +}$ precipitates as the chloride in Group I; $A l^{3 +}$ as the hydroxide in Group III; $C o^{2 +}$ as the sulphide in Group IV; $M g^{2 +}$ is in Group VI. So A-III, B-IV, C-I, D-II.

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ChemistryNEET 2024show ▾

During the preparation of Mohr's salt solution (ferrous ammonium sulphate), which of the following acids is added to prevent hydrolysis of the

F e^{2 +}

ion?

A.concentrated sulphuric acid
B.dilute nitric acid
C.dilute sulphuric acid✓
D.dilute hydrochloric acid

Solution

Dilute sulphuric acid suppresses hydrolysis of $F e^{2 +}$ (which would otherwise give a turbid basic salt) without oxidising it; nitric acid would oxidise $F e^{2 +}$ to $F e^{3 +}$ , and HCl introduces chloride.

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ChemistryNEET 2024show ▾

Given below are certain cations. Using inorganic qualitative analysis, arrange them in increasing group number from 0 to VI. A.

A l^{3 +}

· B.

C u^{2 +}

· C.

B a^{2 +}

· D.

C o^{2 +}

· E.

M g^{2 +}

Choose the correct answer from the options given below:

A.B, C, A, D, E
B.E, C, D, B, A
C.E, A, B, C, D
D.B, A, D, C, E✓

Solution

Qualitative-analysis groups: $C u^{2 +}$ Group II, $A l^{3 +}$ Group III, $C o^{2 +}$ Group IV, $B a^{2 +}$ Group V, $M g^{2 +}$ Group VI. Increasing group order: B, A, D, C, E.

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