Tag: chemistry

Quizzes (490) Questions (9892)

Questions Related to chemistry

Multiple choice chemistry nature of matter heterogenous mixture - colloidal solution and its properties suspensions and colloids mixtures

In the preparation of AgI sol, the excess of $AgNO _{3}$ is added to potassium iodide solution. The particles of the sol will acquire:

  1. negative charge

  2. positive charge

  3. no charge

  4. unpredictable
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

When AgNO3 is in excess, the AgI particles adsorb Ag+ ions from the solution, forming an AgI/Ag+ layer, which gives the colloidal particles a positive charge.

Multiple choice chemistry nature of matter heterogenous mixture - colloidal solution and its properties suspensions and colloids mixtures

Which statement(s) are correct about colloidal state?

  1. The sol particles acquire charge due to preferential adsorption of ions.

  2. Sol particles do not show cataphoresis at isoelectric point.

  3. The stability of protein sol is minimum at its isoelectric point.

  4. The stability of protein sol is due to the presence of charge as well as their extensive solvation nature.
Reveal answer Fill a bubble to check yourself
A,B,C,D Correct answer
Explanation
When two or more ions are present in the dispersion medium, then the colloidal particles absorb preferentially positive or negative ions present in the dispersion medium.

Isoelectric point (pI or IEP) is the pH of a solution or dispersion at which the net charge on the molecules or colloidal particles is zero.

Most globular proteins have minimum solubility at or near their isoelectric point.

The stability of the protein solution is normally because of the presence of charge as well as their extensive solvation nature.

So all the statements are correct.
Multiple choice chemistry nature of matter heterogenous mixture - colloidal solution and its properties suspensions and colloids mixtures

The colligative properties of a colloidal solution compared to the solution of non-electrolyte of same concentration will be:

  1. same

  2. higher

  3. lower

  4. higher or lower
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The colligative properties of a colloidal solution compared to the solution of non-electrolyte of same concentration will be lower as the colloidal solutions are stable due to the presence of charge particle ans also sometimes coagulation happens which reduces the number of particles in the solution and hencem the colligative property.

Multiple choice chemistry nature of matter heterogenous mixture - colloidal solution and its properties suspensions and colloids mixtures

All colloidal solutions show:

  1. very high osmotic pressure.

  2. high osmotic pressure.

  3. low osmotic pressure.

  4. no osmotic pressure.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

All colloidal solutions behave normally as electrolytes and the movement of solvent from solvent to colloidal solution is very less as the concentration gradient for solvent movement is not significant. hence, colloidal solutions show low osmotic pressure.


Hence,option C is correct.

Multiple choice chemistry occurrence of carbon compounds in nature organic compounds allotropes of carbon versatile nature of carbon

Which of the following statements is/are incorrect for diamond?
(a) The refractive index of diamond is highest among solids.
(b) Diamond is hard because all the valence electrons of each carbon atom are involved in bond formation.
(c) Diamond is thermodynamically more stable than graphite.
(d) One carat of diamond represents its weight.

  1. All are correct

  2. a, b and c

  3. a and b

  4. c only
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Graphite is thermodynamically more stable than diamond, diamond is kinetically stable thus statement c is incorrect. 


Diamonds and other gemstones are weighed in metric carats: one carat is equal to 0.2 grams, about the same weight as a paperclip. Carat is just a unit to represent its weight. 


Diamond also possess an extremely high refractive index and fairly high dispersion. 

Hence, the answer is option $\text{D}$

Multiple choice chemistry occurrence of carbon compounds in nature organic compounds allotropes of carbon versatile nature of carbon

The carbon atoms in diamond are bonded to each other by:

  1. ionic bond

  2. coordinate bond

  3. hydrogen bonds

  4. covalent bonds
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The bonds between carbon atoms in diamond are covalent because covalent bonding is the only option when only nonmetals are present.

The rigid network of carbon atoms, held together by strong covalent bonds, makes diamond very hard. This makes it useful for cutting tools, such as diamond-tipped glass cutters and oil rig drills.

Multiple choice chemistry allotropy of carbon organic compounds allotropes of carbon versatile nature of carbon

Fullerene, an allotrope of carbon, has 60 carbon atoms joined together and no other element in it. There are various types of fullerenes. $C _{60}, C _{70}, C _{74}$ and $C _{78}$ are the members of the fullerene family. Identify the property due to which such large numbers of carbon atoms are joined together in this molecule :

  1. Isomerism

  2. Homologous

  3. Catenation

  4. Metamerism
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Catenation is a self-linking property which is maximum present in carbon, because of this property large number of carbon atoms joined together to form molecule.