Do you get confused when you want to use 'so' and 'such' in English??

Let's start with a short sample conversation below (source: www.allearsenglish.com)

A: So Lindsay you are going on vacation pretty soon right?

B: Yeah I am leaving tomorrow.

A: What are you doing?

B: I am going camping in Acadia National Park and whitewater rafting in Maine.

A: Oh wow that should be so exciting.

B: Yeah it is. I have done it once before.

A: It’s  such a good idea for a vacation, getting active and being outside.

B: Yep it’s my kind of vacation.

So in this little conversation how did we use 'so' and how did we use 'such'?

1) So - 'That should be so exciting'.

2) Such - 'It's such a good idea for a vacation'.

What is the key difference between 'so' and 'such'?

According to Cambridge dictionary: Such is a determiner, So is an adverb.

They often have the same meaning of 'very' or 'to this degree':

Those are such good chocolates. Those chocolates are so good.

Such- used with a noun phrase:

• “You are such a great driver.”
• “It has been such a hot summer.”
• “Boston is such a cool city for young people.”

Quick quiz- Can we say “Boston is so a cool city for young people”?

No!

Why not?

It’s because “so” is used with adjective or adverb phrases and not with noun phrases and the noun phrase in this example was “a cool city.”

 So- used with adjective or adverb phrases:

• “This book is so interesting” (adjective)
• “Why do you drive so fast?” (adverb)

Now, change the phrase to use the other one:

• “This house is so dirty.”= “This is such a dirty house.”
• “Potatoe donuts are so yummy.”= “Potatoe donuts are such a yummy breakfast.”