Answer : The correct option is, 
Explanation :
To calculate the pressure of gas we are using ideal gas equation as:

where,
P = pressure of gas = ?
V = volume of gas = 0.046 L
n = number of moles of gas = 3.4
R = gas constant = 8.314 L.kPa/mol.K
T = temperature of gas = 298 K
Now put all the given values in the above formula, we get:


Therefore, the pressure of gas is, 
Answer is:<span>the yield is 50%.
</span>
Chemical reaction: C + O₂ → CO₂.
n(C) = 0.3 mol; amount of substance.
n(O₂) = 0.3 mol.
From chemical reaction: n(C) : n(CO₂) = 1 : 1.
n(CO₂) = 0.3 mol.
M(CO₂) = 44 g/mol; molar mass of caron(IV) oxide.
m(CO₂) = n(CO₂) · M(CO₂).
m(CO₂) =0.3 mol · 44 g/mol.
m(CO₂) = 13.2 g; mass of carbon(IV) oxide.
the yield = 6.6 g ÷ 13.2 g · 100%.
the yield = 50%.