Question

Sodium metal is usually stored under :

• A. Water
• B. Kerosene Oil
• C. Alcohol
• D. Hydrogen

Hint:

Sodium is a very reactive metal. % Option () It reacts violently with {water}. % Option (‚) It reacts with {oxygen and moisture in the air}. % Option (ƒ) It reacts with {alcohols}. {Kerosene oil} acts as a protective blanket, keeping air and moisture away from the sodium, thus preventing these reactions.

Answer 1

The Correct Option is B

Concept: Sodium (Na) is a highly reactive alkali metal. Its storage method must prevent it from reacting with components of the air or other common substances. Step 1: Reactivity of Sodium Sodium is very reactive. It readily reacts with: % Option ({) Oxygen in the air: It tarnishes rapidly in air, forming sodium oxide (\(Na_2O\)) and if moisture is present, sodium hydroxide (NaOH). \[ 4Na(s) + O_2(g) \rightarrow 2Na_2O(s) \] % Option (|) Moisture (water vapor) in the air: It reacts with water to form sodium hydroxide and hydrogen gas. This reaction is exothermic (produces heat). \[ 2Na(s) + 2H_2O(l) \rightarrow 2NaOH(aq) + H_2(g) + \text{heat} \] Step 2: Analyzing storage options % Option (}) (1) Water: Sodium reacts vigorously, even explosively, with water. So, it cannot be stored under water. \[ 2Na(s) + 2H_2O(l) \rightarrow 2NaOH(aq) + H_2(g) \] The heat generated can ignite the hydrogen gas produced. % Option (~) (2) Kerosene Oil: Kerosene is a hydrocarbon oil. Sodium does not react with kerosene. Kerosene also prevents sodium from coming into contact with air (oxygen and moisture). Therefore, sodium is commonly stored under kerosene oil or other similar inert mineral oils. % Option () (3) Alcohol (e.g., Ethanol \(\text{C}_2\text{H}_5\text{OH}\)): Sodium reacts with alcohols (which have an -OH group) to produce sodium alkoxides and hydrogen gas, although the reaction is generally less vigorous than with water. \[ 2Na(s) + 2C_2H_5OH(l) \rightarrow 2NaOC_2H_5(alc) + H_2(g) \] So, alcohol is not suitable for storing sodium. % Option (€) (4) Hydrogen: Storing a reactive metal under a gas is generally not practical for preventing surface reactions with air unless it's a completely sealed, inert atmosphere of pure hydrogen, which is not how it's "usually stored". Also, sodium can form sodium hydride (\(NaH\)) with hydrogen under certain conditions (e.g., heating). Step 3: Identifying the usual storage method Due to its high reactivity with air and water, sodium metal is usually stored under an inert liquid like kerosene oil to protect it from oxidation and reaction with moisture.