One of the following undergoes a reaction

[chemkid1234]

Homework Statement

One of the two pairs of reactants will undergo a reaction. Which one, and what are the products?

Co(OH)₂ (s) + NaOH (aq) ---->

Al(OH)₃ (s) + NaOH (aq) ----->

Homework Equations

N/a

The Attempt at a Solution

I thought it might have something to do with the reactivity series, but I'm not sure how to proceed.

 

[Borek]

Amphoterism is a key word here.

 

[chemkid1234]

So one of the metal hydroxides can act as a base and an acid?

 

[Borek]

Yes.

 

[chemkid1234]

So is the reaction a neutralization reaction?

 

[Borek]

Can be treated this way. Check wiki article on aluminum hydroxide to find out products of the reaction.

 

[chemkid1234]

Okay, according to wikipedia, Al(OH)₃ will form Al(OH)₄^-. So would the other product be Na⁺? Also, how do we know this reaction takes place and the one with Co(OH)₂ doesn't?

 

[Borek]

So would the other product be Na⁺?

Yes.

Also, how do we know this reaction takes place and the one with Co(OH)₂ doesn't?

You have to learn properties of the elements.

 

[chemkid1234]

So because Al is higher on the reactivity series than Co, the Al reaction will take place? Wait, but Na is higher than both of them. So they wouldn't be able to replace it anyway?