pH QUESTION! (1 Viewer)

thekooldude · Feb 19, 2012

Describe the changes to pH in the following reaction mixtures. Be as specific as possible.
a) Excess magnesium reacting with a dilute solution of sulfuric acid.
b) Sodium added to pure water at 25 degrees Celsius.
c) Heating an open bottle of soft drink (& bringing the solution back to 25 degrees Celsius.)

nightweaver066 · Feb 19, 2012

a) $Mg_{(s)} + H_2SO_{4(aq)} \rightarrow MgSO_{4(aq)} + H_{2(g)}$

$Decrease in hydrogen ions in solution, produced salt is neutral, if reaction goes to completion will have a pH of 7$

b) $2Na_{(s)} + 2H_2O_{(l)} \rightarrow 2NaOH_{(aq)} + H_2{(g)}$

$NaOH_{(aq)} \rightarrow Na^+_{(aq)} + OH^-_{(aq)}$

$Sodium hydroxide is formed, a basic salt forming hydroxide ions in solution. pH will increase to around 14$

c) The carbon dioxide dissolving in water is an exothermic reaction, endothermic reaction will be favoured.

The carbon dioxide will diffuse from the drink, meaning no carbonic acid, decrease in hydrogen/hydronium ions, pH will increase

Dylanamali · Feb 22, 2012

^ correct, nightweaver appears VERY on top of his chemistry knowledge.

someth1ng · Feb 22, 2012

The only thing I get confused about is the MgSO4 part - isn't MgSO4 insoluble or very slightly soluble?

nightweaver066 · Feb 22, 2012

someth1ng said:
The only thing I get confused about is the MgSO4 part - isn't MgSO4 insoluble or very slightly soluble?

It is soluble.

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pH QUESTION! (1 Viewer)

thekooldude

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nightweaver066

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Dylanamali

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someth1ng

Retired Nov '14

nightweaver066

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