Missing question:
Chemical reaction: H₂ <span>+ 2ICl → 2HCl + I</span>₂.
t₁ = 5 s.
t₂ = 15 s.
c₁ = 1,11 M = 1,11 mol/L.
c₂ = 1,83 mol/L.
rate of formation = Δc ÷ Δt.
rate of formation = (c₂ - c₁) ÷ (t₂ - t₁).
rate of formation = (1,83 mol/L - 1,11 mol/L) ÷ (15 s - 5 s).
rate of formation = 0,72 mol/L ÷ 10 s.
rate of formation = 0,072 mol/L·s.
In an unknown liquid, the percentage composition with respect to carbon, hydrogen and iodine is 34.31%, 5.28% and 60.41% respectively.
Let the mass of liquid be 100 g thus, mass of carbon, hydrogen and oxygen will be 34.31 g, 5.28 g and 60.41 g respectively.
To calculate molecular formula of compound, convert mass into number of moles as follows:

Molar mass of carbon, hydrogen and iodine is 12 g/mol, 1 g/mol and 126.90 g/mol.
Taking the ratio:

Putting the values,

Thus, molecular formula of compound will be
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A graph shows a relationship between two variables: independent and dependent. The dependent variable is in the y-axis, while the independent variable is in the x-axis. When it says, plot velocity against time, that means that
velocity is in the y-axis in meters per second, and time is in the x-axis in seconds. An example of a velocity vs time graph is shown in the attached picture. In this example, the motion is in constant acceleration. This is because it is linear, thereby, the slope is constant. If you want to find the instantaneous velocity at a certain time, create a vertical line from the x-axis until it reaches the diagonal line. Then, draw a horizontal line towards the y-axis to know the value of the velocity.