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Chemical formula

Example: Balanced Chemical Equations with Subscripts Water: $$\ce{H2O}$$ Carbon dioxide: $$\ce{CO2}$$ Iron(III) hydroxide (Rust reaction): $$\ce{4Fe + 3O2 + 6H2O -> 4Fe(OH)3}$$ Copper(II) sulfate pentahydrate: $$\ce{CuSO4 * 5H2O}$$ Chemical Formulas in Chemistry Chemical formulas are the symbolic representations of chemical substances. They show the elements present in a compound and the ratio in which the atoms of these elements combine. Chemical formulas are essential for understanding the composition, structure, and behavior of compounds in chemical reactions. 1. What is a Chemical Formula? A chemical formula uses symbols of elements and numerical subscripts to represent the composition of a substance. For example, the formula for water is: $$ \ce{H2O} $$ This indicates that each water molecule is made up of 2 atoms of hydrogen and 1 atom of oxygen. 2. Types of Chemical Formulas Empirical Formula Molecular Formula Structural Formula...

10 MCQ On Chromatography

In this topic , we shall study the techniques of chromatography . Here, we were going to explore how mixed liquids can be separate out even if they are are miscible. It's a famous  technique that is used to separate mixtures into their compounds , purify compounds , isolation of compounds , identification of components of organic  and also to test the purity of compounds . It's general principle is phase rule.

Let's discuss about the principle of chromatography .
Principle : Here, there are two phase are used to apply for separation of mixture of compounds . The mixture of substances is applied onto a stationary phase . This stationary phase may be a solid or liquid . A gas , a pure solvent or a mixture of solvents are allowed to move slowly over stationary phase . We will see that the components of mixture gradually separated slowly  from each other. The moving phase is referred as mobile phase . 

We have an example of it. A mixture of red and blue ink can be separated by the chromatography method.  A drop of red and blue mixed ink is placed on chromatogram. Less adsorbed , component of the mixed ink will move with mobile phase and the more adsorbed component will be continued to stick with the stationary phase .

We have some objectives to clear the concept . Let's have a look .

Here are 10 MCQs on Chromatography:

1. Which of the following is NOT a type of chromatography?

   A. Gas Chromatography
   B. Liquid Chromatography
   C. Ion Exchange Chromatography
   D. Mass Spectrometry

Answer : D. Mass Spectrometry

2. In Thin Layer Chromatography (TLC), the stationary phase is typically:

   A. A liquid
   B. A gas
   C. A solid adsorbent
   D. A polymer gel

Answer:   C.  A solid adsorbent

3. The retention factor (Rf) value in TLC is:

  A. The distance traveled by the solvent front divided by the distance traveled by the solute
  B. The distance traveled by the solute divided by the distance traveled by the solvent front
  C. The ratio of the molecular weights of the solute and solvent
  D. The ratio of the densities of the solute and solvent

Answer: B. The distance traveled by the solute divided by the distance traveled by the solvent front

4. In Gas Chromatography (GC), the mobile phase is:

   A. A liquid solvent
   B. A gas
   C. A solid adsorbent
   D. A liquid stationary phase

Answer :   B. A gas

5. Which technique is best suited for separating volatile compounds?

   A. Thin Layer Chromatography (TLC)
   B. Paper Chromatography
   C. Gas Chromatography (GC)
   D. High-Performance Liquid Chromatography (HPLC)

Answer: C. Gas Chromatography (GC)

6. In High-Performance Liquid Chromatography (HPLC), the pressure applied to the mobile phase is:

   A. Low
   B. High
   C. Medium
   D. Negligible

Answer:    B. High

7. What is the primary principle behind ion exchange chromatography?

   A. Differences in molecular weight
   B. Differences in charge
   C. Differences in volatility
   D. Differences in solubility

Answer: B. Differences in charge

8. Which type of chromatography is often used to separate proteins based on their size and shape?

   A. Gas Chromatography (GC)
   B. Thin Layer Chromatography (TLC)
   C. Size Exclusion Chromatography
   D. Ion Exchange Chromatography

Answer:  C. Size Exclusion Chromatography

9. Chromatography is used for the purification of : 

  A. Solids 
  B. Liquids 
  C. Gases
  D. All of the above 

Answer: D. All of the above 

10. Chromatography is based on general principle of : 
  A. Interphase separation 
  B. Phase rule 
  C. Phase operation
  D. Sublimation 

Answer: Phase rule 

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