In a compound C, H, N atoms are present in 9 : 1 : 3.5 by weight. Molecular weight of compound is 108. Its molecular formula is:a)C2H6N2b)C3H4Nc)C6H8N2d)C9H12N3Correct answer is option 'C'. Can you explain this answer?

Question

Answer

72+28+8=108
You can do option checking by finding the molecular weight of each option which takes 30-40 seconds rather than doing the whole method which will take 3-4 minutes without any gurantee of answer

Answer

C6H8N2 implies 12×6 : 1×8 : 14×2 that is 72:8:28 or simply 9:1:3•5.
Or it's only option C whose molecular mass is 108.So u can check this directly .

Answer

Given:
- Compound contains C, H, and N atoms in a ratio of 9:1:3.5 by weight.
- Molecular weight of the compound is 108.

To find:
The molecular formula of the compound.

Solution:

Step 1: Calculate the number of moles
- Assume that the compound contains 9x grams of carbon, x grams of hydrogen, and 3.5x grams of nitrogen.
- Calculate the number of moles for each element using their atomic masses:
- Moles of Carbon (C) = (9x) / (atomic mass of Carbon)
- Moles of Hydrogen (H) = x / (atomic mass of Hydrogen)
- Moles of Nitrogen (N) = (3.5x) / (atomic mass of Nitrogen)

Step 2: Determine the empirical formula
- Divide the number of moles of each element by the smallest number of moles obtained from step 1.
- This will give us the simplest whole number ratio of atoms in the compound.

Step 3: Calculate the empirical formula mass
- Multiply the atomic masses of each element by the number of atoms in the empirical formula.
- Add up the masses of all the atoms to get the empirical formula mass.

Step 4: Calculate the empirical formula ratio
- Divide the molecular weight of the compound by the empirical formula mass.
- This will give us the number of empirical formula units present in the compound.

Step 5: Determine the molecular formula
- Multiply the subscripts of the empirical formula by the number of empirical formula units obtained from step 4.
- This will give us the molecular formula of the compound.

Explanation:
- The atomic masses of C, H, and N are approximately 12, 1, and 14 respectively.
- Using the given ratio, we can assume that the compound contains 9 grams of carbon, 1 gram of hydrogen, and 3.5 grams of nitrogen.
- Calculating the number of moles for each element gives us:
- Moles of Carbon (C) = 9 / 12 = 0.75 moles
- Moles of Hydrogen (H) = 1 / 1 = 1 mole
- Moles of Nitrogen (N) = 3.5 / 14 = 0.25 moles
- Dividing these values by the smallest number of moles (0.25 moles) gives us the empirical formula ratio: C3H4N.
- The empirical formula mass can be calculated as follows:
- Carbon: 0.75 moles * 12 g/mol = 9 g/mol
- Hydrogen: 1 mole * 1 g/mol = 1 g/mol
- Nitrogen: 0.25 moles * 14 g/mol = 3.5 g/mol
- Empirical formula mass = 9 g/mol + 1 g/mol + 3.5 g/mol = 13.5 g/mol
- Dividing the molecular weight of the compound (108 g/mol) by the empirical formula mass (13.5 g/mol) gives us the number of empirical formula units in the compound:

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