1990 DAT Gchem question 51

[yahoogoogle]

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which of the following substances would produce a basic solution when dissolved in water?

1. CO2
2. H3AsO4
3. HCl
4. Na2O
5. SO3

 

[yahoogoogle]

anyone has idea?

 

[PD3]

If SO3 is an anion, then I would say SO3. I don't really know.

 

[DMDreaming]

which of the following substances would produce a basic solution when dissolved in water?

1. CO2
2. H3AsO4
3. HCl
4. Na2O
5. SO3

I'm not sure but isn't CO2 basic. I'm thinking about oxygen/CO2 exchange in the blood and think it's driven by the basic pH of CO2. I can't remember for sure. Will look it up and repost if necessary.

 

[fsapien]

4. Na2O
Metal oxides form basic solutions (non-metal oxides form acidic solutions).
I think.

 

[joonkimdds]

which of the following substances would produce a basic solution when dissolved in water?

1. CO2
2. H3AsO4
3. HCl
4. Na2O
5. SO3

I am not sure but I think HCl cannot be the answer becuz it will dissolve and produce H and Cl. H is acid....
I am not sure about the others...
Oh~! I think H3AsO4 also dissolves and produces H + H2AsO4 🙄
so that means it also makes acid.
That's as far as my brain goes now.
All i study about acid and base is that acid= H , base = OH 😛
I don't know anything beyond this 🙁

 

[denttiger]

Where exactly are you getting all these questions?

 

[Chga]

i would say Na2O.
just b/c it can accept extra hydrogens..... what is the answer?

 

[joonkimdds]

i would say Na2O.
just b/c it can accept extra hydrogens..... what is the answer?

wait...now i remember that there are 3 different ways to define acid-base 🙂
but how do we know that Na2O can accept extra hydrogen?

 

[domonas]

The answer is Na2O

Na is the salt of a strong base (NaOH). It's just that simple.

if you forgot which are the 6 common strong bases

LiOH, KOH, NaOH
Ca(OH)2, Sr(OH)2, Ba(OH)2

in the same light, if they asked a ? regarding a solution that'll be acidic, find the anion of strong acids

the strong acids are
HCl, HBr, HI
HNO3, H2SO4, HClO4

 

[joonkimdds]

The answer is Na2O

Na is the salt of a strong base (NaOH). It's just that simple.

if you forgot which are the 6 common strong bases

LiOH, KOH, NaOH
Ca(OH)2, Sr(OH)2, Ba(OH)2

in the same light, if they asked a ? regarding a solution that'll be acidic, find the anion of strong acids

the strong acids are
HCl, HBr, HI
HNO3, H2SO4, HClO4

does that mean the key to solve this problem is coming from memorizing 6 common strong base and 6 common strong acid otherwise we can't solve this problem?

 

[domonas]

does that mean the key to solve this problem is coming from memorizing 6 common strong base and 6 common strong acid otherwise we can't solve this problem?

i think that's the easiest way to go.

 

[domonas]

I'm not sure but isn't CO2 basic. I'm thinking about oxygen/CO2 exchange in the blood and think it's driven by the basic pH of CO2. I can't remember for sure. Will look it up and repost if necessary.

actually, it's the bicarbonate ion, HCO3- (among other things) that determine pH.

 

[DMDreaming]

actually, it's the bicarbonate ion, HCO3- (among other things) that determine pH.

Thanks! I just remembered that the pH change altered oxygen affinity but couldn't remember what changed the pH.

 

[Danny289]

Na2O + H2O =======> 2 NaOH (answer)