Question

On reaction of glycerol and sodium metal is 1: 2 ratio, the compound obtained is (A) OCC(O)CO (B) NOCC(O)CO (C) NOCC(O)CO (D) COCC(O)CC(C)O

Short answer

The compound obtained from the reaction of glycerol and sodium metal in a 1:2 ratio is not exactly described by any of the given options. However, choice (A) - OCC(O)CO - is the closest match.

Step-by-step solution

Identify the structure of glycerol

Glycerol is a simple polyol (sugar alcohol) compound with the molecular formula C3H8O3. Its structure consists of three carbon atoms, each bearing a hydroxyl group (–OH), as well as a hydrogen atom. The structure of glycerol looks like this: HOCH2CH(OH)CH2OH.

Write the balanced chemical equation for the reaction

In the given problem, glycerol reacts with sodium metal (Na) in a 1:2 ratio. This suggests that two sodium atoms will replace two hydrogen atoms from the hydroxyl groups of glycerol. The balanced chemical equation for the reaction is: HOCH2CH(OH)CH2OH + 2 Na ⟶ HOCH2CH(ONa)CH2ONa + H2

Identify the compound formed in the reaction

According to the chemical equation in the previous step, the compound formed in the reaction is HOCH2CH(ONa)CH2ONa. The given choices can be expressed as the corresponding molecular formulas: (A) OCC(O)CO - C3H6O3 (B) NOCC(O)CO - C3H5NO3 (C) NOCC(O)CO - C3H5NO3 (Same as B) (D) COCC(O)CC(C)O - C5H10O3 By comparing these molecular formulas to the compound obtained from the reaction (HOCH2CH(ONa)CH2ONa), we can see that none of the choices directly match. However, choice (A) is the closest match; it can be rewritten in a different representation more similar to the reaction product: HOCH2CH(O)CH2O In conclusion, the compound obtained from the reaction is not exactly described by any of the options given. However, choice (A) - OCC(O)CO - is the closest match.

Key concepts

Glycerol Chemical Reaction

When thinking about organic chemistry, it's important to understand how various compounds react. One fundamental reaction is that involving glycerol, a simple polyol. A polyol is an organic compound containing multiple hydroxyl groups. Glycerol, in particular, has three -OH groups, making it trihydric.
In the presence of reactive metals such as sodium (Na), glycerol undergoes a substitution reaction where sodium replaces one or more hydrogen atoms in the hydroxyl groups. It's key to visualize the structure of glycerol: HOCH₂CH(OH)CH₂OH, where each carbon is bonded to a hydroxyl group.
During the reaction of glycerol with sodium metal, hydrogen is displaced from the glycerol, yielding a new compound and hydrogen gas. This type of reaction is common in polyols due to their multiple reactive hydroxyl sites.

Sodium Metal Reaction

Sodium metal is highly reactive, particularly when it comes into contact with substances bearing hydroxyl groups, like polyols. The fundamental concept to grasp here is that sodium reacts with the hydrogen atoms in the hydroxyl groups to give off hydrogen gas and form sodium alkoxide.
Understanding the reactivity of sodium is vital for safely handling it and predicting the products of its reactions. In our example, two moles of sodium react with one mole of glycerol, illustrating the typical 1:2 stoichiometry for such reactions.

Visualizing the Reaction

It helps to visualize sodium slicing off the hydrogen atoms, as in the equation: 2 Na + 2 HO—> 2 NaO— + H₂. Such visualizations can aid in comprehending the powerful and often vigorous nature of reactions involving alkali metals like sodium.

Chemical Equation Balancing

A central skill in chemistry is the ability to balance chemical equations. This is the process of ensuring that the number of atoms for each element is the same on both sides of the equation. This reflects the law of conservation of mass, which states that matter cannot be created or destroyed in a chemical reaction.
The reaction between glycerol and sodium is an excellent opportunity to practice balancing equations. For instance, we start with the equation: HOCH₂CH(OH)CH₂OH + Na ⟶ ... Then, we add coefficients to balance the sodium, hydrogen, carbon, and oxygen atoms. The result should be a complete and balanced equation: HOCH₂CH(OH)CH₂OH + 2 Na ⟶ HOCH₂CH(ONa)CH₂ONa + H₂. It's critical to ensure that every atom on the reactant side appears on the product side.

Polyols in Organic Chemistry

Polyols are a group of organic compounds that are characterized by the presence of multiple hydroxyl (-OH) groups. These compounds, like glycerol, are widely used in the food, pharmaceutical, and chemical industries due to their versatility and functionality.
Polyols can participate in a variety of chemical reactions, including oxidation, esterification, and of course, reactions with metals as discussed previously. They are also key intermediates in the synthesis of polymers, fats, and other important biomolecules.

Functionality of Polyols

Their hydrophilicity, solubility, and non-toxic nature make polyols suitable for various applications, including as sweeteners and as humectants, which are substances that help retain moisture. These multi-functional groups in polyols provide reactive sites for chemical transformations, paving the way for the synthesis of a multitude of products and derivatives in organic chemistry.