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Carbon and its Compounds - Ethanol and Ethanoic acid

Grade 10CBSE

Review the key concepts, formulae, and examples before starting your quiz.

🔑Concepts

Ethanol (C2H5OHC_2H_5OH) is a colorless liquid at room temperature with a distinct smell and burning taste. It is soluble in water in all proportions.

Ethanol reacts with Sodium (NaNa) to form sodium ethoxide (CH3CH2ONaCH_3CH_2ONa) and evolve hydrogen gas (H2H_2).

Dehydration of Ethanol: Heating ethanol at 443 K443\text{ K} with excess concentrated H2SO4H_2SO_4 results in the formation of ethene (CH2=CH2CH_2=CH_2). Here, H2SO4H_2SO_4 acts as a dehydrating agent.

Ethanoic Acid (CH3COOHCH_3COOH) belongs to the group of carboxylic acids. A 58%5-8\% solution of ethanoic acid in water is called vinegar.

Glacial Acetic Acid: The melting point of pure ethanoic acid is 290 K290\text{ K}. It often freezes during winter in cold climates, giving it this name.

Esterification Reaction: Ethanoic acid reacts with absolute ethanol in the presence of an acid catalyst to give an ester (CH3COOC2H5CH_3COOC_2H_5), which is characterized by a sweet smell.

Saponification: Esters react in the presence of an alkali like NaOHNaOH to give back the alcohol and the sodium salt of the carboxylic acid (CH3COONaCH_3COONa).

Reaction with Carbonates: Ethanoic acid reacts with carbonates (Na2CO3Na_2CO_3) and hydrogencarbonates (NaHCO3NaHCO_3) to produce salt, water, and carbon dioxide (CO2CO_2) gas.

📐Formulae

2Na+2CH3CH2OH2CH3CH2ONa+H22Na + 2CH_3CH_2OH \rightarrow 2CH_3CH_2ONa + H_2\uparrow

CH3CH2OHHot conc. H2SO4CH2=CH2+H2OCH_3CH_2OH \xrightarrow{\text{Hot conc. } H_2SO_4} CH_2=CH_2 + H_2O

CH3COOH+CH3CH2OHAcidCH3COOCH2CH3+H2OCH_3COOH + CH_3CH_2OH \xrightarrow{\text{Acid}} CH_3COOCH_2CH_3 + H_2O

CH3COOC2H5NaOHC2H5OH+CH3COONaCH_3COOC_2H_5 \xrightarrow{NaOH} C_2H_5OH + CH_3COONa

2CH3COOH+Na2CO32CH3COONa+H2O+CO22CH_3COOH + Na_2CO_3 \rightarrow 2CH_3COONa + H_2O + CO_2\uparrow

CH3COOH+NaHCO3CH3COONa+H2O+CO2CH_3COOH + NaHCO_3 \rightarrow CH_3COONa + H_2O + CO_2\uparrow

💡Examples

Problem 1:

What happens when ethanol is oxidized by alkaline KMnO4KMnO_4?

Solution:

Ethanol is converted into ethanoic acid (CH3COOHCH_3COOH).

Explanation:

Alkaline KMnO4KMnO_4 acts as an oxidizing agent, adding oxygen to ethanol: CH3CH2OHAlkaline KMnO4+HeatCH3COOHCH_3CH_2OH \xrightarrow{\text{Alkaline } KMnO_4 + \text{Heat}} CH_3COOH

Problem 2:

Explain the chemical test to distinguish between ethanol and ethanoic acid using sodium hydrogencarbonate (NaHCO3NaHCO_3).

Solution:

Ethanoic acid reacts with NaHCO3NaHCO_3 to produce brisk effervescence of CO2CO_2 gas, while ethanol does not react.

Explanation:

Carboxylic acids like CH3COOHCH_3COOH are acidic enough to decompose carbonates and hydrogencarbonates, releasing CO2CO_2, whereas alcohols like C2H5OHC_2H_5OH are neutral/very weakly acidic and fail this test.

Problem 3:

Write the products formed when ethanoic acid reacts with sodium hydroxide (NaOHNaOH).

Solution:

The products are Sodium Ethanoate (CH3COONaCH_3COONa) and water (H2OH_2O).

Explanation:

This is a neutralization reaction between an acid and a base: CH3COOH+NaOHCH3COONa+H2OCH_3COOH + NaOH \rightarrow CH_3COONa + H_2O

Ethanol and Ethanoic acid - Revision Notes & Key Formulas | CBSE Class 10 Science