All Free Chemistry MCQs with Answers

• A. A solution of AgNO3 in HNO3
• B. Colloidal solution of gold
• C. A colloidal solution of platinum
• D. A colloidal solution of palladium

Explanation: Purple of Cassius is colloidal solution of gold. It is formed by the reaction of gold salts with tin(II) chloride.

• A. Some times physical adsorption pass over to chemisorption on increasing the temperature of the system.
• B. Oxygen is adsorbed on charcoal but on desorption it also releases CO and CO2
• C. Only lighter gases show physical adsorption at low temp.
• D. Activation energy of chemisorption > activation energy of physical adsorption

Explanation: All gases show the physical adsorption at low temperature.

• A. presence of different types of foreign particles depending upon the method of preparation of the colloid
• B. different concentrations of gold
• C. various forms of gold
• D. presence of different size of the colloidal particles obtained in different methods.

Explanation: Colloidal solutions of gold prepared by different methods have different colors due to the presence of different size of the colloidal…

• A. the clouds are attracted towards the electrical charge on the earth.
• B. large amount of water is present in the cloud
• C. dense clouds are present in the upper atmosphere
• D. mutual discharge of oppositely charged clouds resulting in the coagulation of water droplets

Explanation: This is due to mutual discharge oppositely charge clouds resulting in the coagulation of water droplets.

• A. Coagulation of sand
• B. sedimentation of common salt
• C. deposition of MgCl2
• D. mutual coagulation

Explanation: Sand is a negatively charged colloidal particles, which is carried by river to the ocean which is a vast reservoir of Na+, Mg+,K+, ion.

• A. It seals the blood cell
• B. Blood starts flowing in reverse direction
• C. The blood is coagulated and the blood cell is sealed
• D. None

Explanation: Blood is a colloidal solution of albuminoid substance in water and alubminoid is negatively charged.

• A. disperson effect
• B. scattering
• C. reflection
• D. transmission

Explanation: The sky or water in the sea looks blue because the light of long wavelength gets absorbed, and light of short wavelength (blue light) gets…

• A. Silica gel
• B. Alumina
• C. Fuller's earth
• D. Activated charcol

Explanation: The adsorbents commonly employed for chromatography are alumina (specially prepared for this purpose), magnesium oxide, and sucrose.

• A. Cl− ions
• B. Fe3+ ions
• C. OH− ions
• D. Fe+2 ions

Explanation: Fe(OH)3 is a positive sol. The positive charge is due to the preferential adsorption of Fe3+ ions.

• A. Colloids
• B. Crystalloids
• C. Electrolytes
• D. Non electrolytes

Explanation: Solutions which can diffuse readily through parchment membrane are crystalloids.

• A. Is easy to spray at high altitude
• B. Is easy to synthesizes
• C. Has crystal structure similar to ice
• D. Is insoluble in water

Explanation: AgI has the crystal structure similar to ice. Hence it can act as a nucleus for the precipitation of the water molecules and causes rain.

• A. 0.1(N) Zn(NO3)2
• B. 0.1(N) Na3PO4
• C. 0.1(N) ZnSO4
• D. 0.1(N) AlCl3

Explanation: More the valency of cation greater will be its coagulating power as per hardy schulze rule.

• A. 0.25
• B. 25
• C. 250
• D. 2.5

Explanation: 250 mg of X is present in 100 ml of colloidal sol of gold. By definition, gold no.

• A. Convection currents in the fluid
• B. Unequal bombardments by the molecules of the dispersion medium on colloidal particles.
• C. Setting of dispersed phase under gravity.
• D. Thermal gradient in the medium.

Explanation: Unequal bombardments of solvent particles on colloidal particles cause zigzag motion.

• A. 0. 025
• B. 0.25
• C. 2.5
• D. 250

Explanation: According to the definition of gold number, in this case starch has gold number of 250.

• A. 40
• B. 20
• C. 60
• D. 80

Explanation: The minimum amount of lyophilic colloid in mg which prevents the coagulation of 10 ml gold sol by 1 ml of 10% NaCl solution.

• A. Diffraction
• B. Interferences
• C. Refraction
• D. Spectroscopy

Explanation: Spectroscopy is like the CSI of light! It's all about studying how light interacts with matter.

• A. Frequency
• B. Energy
• C. Wavelength
• D. All of the above

Explanation: (a) Frequency: This is like the beat of the light wave, how fast it's waving.

• A. Low velocity invisible rays
• B. High velocity invisible rays
• C. High velocity visible rays
• D. Low velocity visible rays

Explanation: X-rays are high-frequency electromagnetic radiations having wavelengths between 0.01-10 nm, way beyond the visible range that is between…

• A. Wavelengths
• B. Intensities of electromagnetic radiations emitted by atoms
• C. Intensities of electromagnetic radiations absorbed by atoms
• D. All of these options
• E. Both B and C

Explanation: The correct answer is D: All of these options. Atomic spectra encompass the study of both the wavelengths and the intensities of…