10 gram of hydrofluoric acid gas occupies 5.6 litre of volume at ntp i...
**Given information:**
- 10 grams of hydrofluoric acid gas (HF) occupies 5.6 liters of volume at NTP (Normal Temperature and Pressure).
- We are asked to determine the molecular formula of the gas.
**Step 1: Calculate the moles of the gas**
To determine the molecular formula, we first need to calculate the number of moles of the gas using the ideal gas equation:
PV = nRT
Where:
P = Pressure (at NTP, pressure is 1 atm)
V = Volume (5.6 liters)
n = Number of moles (to be calculated)
R = Ideal gas constant (0.0821 L·atm/(mol·K))
T = Temperature (at NTP, temperature is 273 K)
Substituting the given values into the equation:
(1 atm) * (5.6 L) = n * (0.0821 L·atm/(mol·K)) * (273 K)
n = (1 atm * 5.6 L) / (0.0821 L·atm/(mol·K) * 273 K)
n = 0.235 moles
**Step 2: Determine the empirical formula**
The empirical formula gives the simplest whole number ratio of atoms in a compound. To determine the empirical formula of hydrofluoric acid gas (HF), we need to find the ratio of hydrogen to fluorine atoms.
- Hydrogen: The molar mass of hydrogen is 1 g/mol. In 10 grams of HF, the number of moles of hydrogen can be calculated as:
(10 g) / (1 g/mol) = 10 moles
- Fluorine: The molar mass of fluorine is 19 g/mol. In 10 grams of HF, the number of moles of fluorine can be calculated as:
(10 g) / (19 g/mol) = 0.526 moles
To find the ratio, we divide the number of moles of each element by the smallest number of moles:
Hydrogen: 10 moles
Fluorine: 0.526 moles
Dividing both values by 0.526 moles (the smallest number of moles), we get:
Hydrogen: 10 moles / 0.526 moles = 19
Fluorine: 0.526 moles / 0.526 moles = 1
Therefore, the empirical formula of the gas is HF.
**Step 3: Determine the molecular formula**
The empirical formula of HF gives us the ratio of hydrogen to fluorine atoms. To determine the molecular formula, we need to find the actual number of atoms in the molecule.
Since the empirical formula HF already represents one hydrogen atom and one fluorine atom, the molecular formula will also be HF.
**Answer:**
The molecular formula of the gas is **HF (option A)**.
10 gram of hydrofluoric acid gas occupies 5.6 litre of volume at ntp i...
5.6 L of acid weighs 10g at ntp, so
22.4 L of acid weighs 40g at ntp.
therefore M.W of acid = 40g. ratio of H:F is 1:1
m.w : (H=1, F=19) Let formula be (HF)n
so, n+19n=40 , n=2 so acid is H2F2
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