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20 ml of a hydro carbon requires 100 ml ...

20 ml of a hydro carbon requires 100 ml of oxygen for complete combustion. In this reaction 60 ml of carbondioxide is produced. The formula of hydro carbon is

A

`C_(2)H_(4)`

B

`C_(3)H_(6)`

C

`C_(3)H_(8)`

D

`C_(6)H_(6)`

Text Solution

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The correct Answer is:
To determine the formula of the hydrocarbon based on the given data, we can follow these steps: ### Step 1: Write the general equation for the combustion of a hydrocarbon. The general combustion reaction for a hydrocarbon (C_xH_y) can be written as: \[ C_xH_y + O_2 \rightarrow CO_2 + H_2O \] ### Step 2: Identify the volumes given in the problem. From the problem, we have: - Volume of hydrocarbon (C_xH_y) = 20 ml - Volume of oxygen (O_2) = 100 ml - Volume of carbon dioxide (CO_2) produced = 60 ml ### Step 3: Use the stoichiometry of the reaction. From the combustion reaction, we can deduce that: - For every 1 volume of hydrocarbon, we need a certain amount of oxygen and produce a certain amount of carbon dioxide and water. ### Step 4: Relate the volumes of reactants and products. According to the stoichiometry of the reaction: - If 1 volume of hydrocarbon produces 1 volume of CO_2, then: \[ \text{Volume of CO}_2 = \text{Volume of hydrocarbon} \times \frac{60 \text{ ml}}{20 \text{ ml}} = 3 \text{ volumes of hydrocarbon} \] - Therefore, if 20 ml of hydrocarbon produces 60 ml of CO_2, it indicates that the hydrocarbon contains 3 carbon atoms. ### Step 5: Determine the number of hydrogen atoms. We know that: - The complete combustion of hydrocarbons also produces water (H_2O). - The volume of oxygen used can be related to the number of hydrogen atoms in the hydrocarbon. - The balanced equation shows that for every 1 mole of C_xH_y, \((x + \frac{y}{4})\) moles of O_2 are required. ### Step 6: Calculate the required oxygen. From the stoichiometry, we know: - 100 ml of O_2 is used for 20 ml of hydrocarbon. - The ratio of oxygen to hydrocarbon is: \[ \frac{100 \text{ ml}}{20 \text{ ml}} = 5 \] - This means that for every 1 volume of hydrocarbon, 5 volumes of O_2 are required. ### Step 7: Set up the equation based on carbon and hydrogen. From the combustion reaction: - For 3 carbon atoms (C) in the hydrocarbon, we need 3 CO_2. - For the hydrogen atoms, we can set up the equation based on the oxygen used: \[ \text{Oxygen used} = \frac{3}{2} + \frac{y}{4} \] - We know that 100 ml of O_2 is used, which corresponds to 5 volumes: \[ 5 = \frac{3}{2} + \frac{y}{4} \] ### Step 8: Solve for y (the number of hydrogen atoms). Rearranging the equation: \[ 5 - \frac{3}{2} = \frac{y}{4} \] \[ \frac{10}{2} - \frac{3}{2} = \frac{y}{4} \] \[ \frac{7}{2} = \frac{y}{4} \] Multiplying both sides by 4: \[ y = 14 \] ### Step 9: Write the formula of the hydrocarbon. Now we have: - x (number of carbon atoms) = 3 - y (number of hydrogen atoms) = 14 Thus, the formula of the hydrocarbon is: \[ C_3H_{14} \] ### Final Answer: The formula of the hydrocarbon is \( C_3H_{14} \).

To determine the formula of the hydrocarbon based on the given data, we can follow these steps: ### Step 1: Write the general equation for the combustion of a hydrocarbon. The general combustion reaction for a hydrocarbon (C_xH_y) can be written as: \[ C_xH_y + O_2 \rightarrow CO_2 + H_2O \] ### Step 2: Identify the volumes given in the problem. From the problem, we have: ...
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