Match List I with List II
| LIST I | LIST II |
| A. Haemoglobin | I. Negatively charged sol |
| B. Acid dye stuff | II. Methylene blue sol |
| C. Gold solution | III. Positively charged sol |
| D. Basic dye stuff | IV. Eosin |
Choose the correct answer from the options given below:
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → A-III, B-IV, C-I, D-II
A colloidal particle carries an electric charge, either positive or negative, which is the same on all particles of one sol. Metal sols and acid dyes give negatively charged sols; basic dyes, haemoglobin and hydrated metal oxides give positively charged sols.
(A) Haemoglobin — This matches (III) Positively charged sol. Haemoglobin (blood) forms a positively charged sol.
(B) Acid dye stuff — This matches (IV) Eosin. Eosin is an acid dye; acid dyes such as eosin and congo red give negatively charged sols.
(C) Gold solution — This matches (I) Negatively charged sol. Metal sols of copper, silver and gold are negatively charged.
(D) Basic dye stuff — This matches (II) Methylene blue sol. Methylene blue is a basic dye and gives a positively charged sol.
Note: This question is from the pre-rationalised NCERT book (2022-23). The topic is not there in the latest NCERT book (2026-27), and it is also out of the CUET 2026 syllabus.
NCERT (Pre-rationalised edition, 2022-23):
Charge on Colloidal Particles – “Colloidal particles always carry an electric charge. The nature of this charge is the same on all the particles in a given colloidal solution and may be either positive or negative. A list of some common sols with the nature of charge on their particles is given below:”
| Positively charged sols | Negatively charged sols |
|---|---|
| Hydrated metallic oxides, e.g., Al2O3.xH2O, CrO3.xH2O and Fe2O3.xH2O, etc. | Metals, e.g., copper, silver, gold sols. |
| Basic dye stuffs, e.g., methylene blue sol. | Metallic sulphides, e.g., As2S3, Sb2S3, CdS sols. |
| Haemoglobin (blood) | Acid dye stuffs, e.g., eosin, congo red sols. |
| Oxides, e.g., TiO2 sol. | Sols of starch, gum, gelatin, clay, charcoal, etc. |