Magnesium can interfere with the measurement of the calcium concentration in water samples using colorimetric tests. Write a balanced chemical equation for the reaction of dissolved magnesium chloride with sodium hydroxide to form magnesium hydroxide as a precipitate and sodium chloride. (Reactants -> Products)

Explanation:

Hello.

In this case, since aqueous magnesium chloride reacts with aqueous sodium hydroxide, a precipitate product, magnesium hydroxide is formed as well as aqueous sodium chloride as shown below:

However, since there are two chlorine atoms at the reactants we need a 2 before NaCl on the products in order to balance it. Moreover, there one OH at the  reactants and two OH at the products, that is why we also add a 2 before NaCl as shown below:

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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