A solution is prepared by dissolving 2.61 g ethanol (C2H5OH) in 16.2 g water. What is the molality (mol/kg) of C2H5OH in the solution?

3.50 molal

Explanation:

Molality → Moles of solute / kg of solvent.

Let's convert the solvent's mass from g to kg

16.2 g . 1kg / 1000 g = 0.0162 kg

Let's determine the moles from the solute

2.61 g . 1 mol / 46 g = 0.0567 moles

Molality → 0.0567 mol / 0.0162 kg = 3.50 m

as given the equation is

2al + 6 hcl > 2 alcl3 + 3 h2(g)

as per equation two moles of aluminum reacts with six moles of hcl to give two moles of alcl3 and three moles of hydrogen gas

given: three moles of al are present and 7 moles of hcl

for three moles of aluminum nine moles of hcl will be required

however as 7 moles of hcl are present so the limiting reagent is hcl

hcl is going to decide the number of moles of product formed

when six moles of hcl are present = 3 moles of h2 are formed

when one mole of hcl is present == 3/6 mole sof h2 will be formed

when 7 moles of hcl are present = 3 x 7/ 6 moles of h2 will be formed = 3.5 moles of h2