What exactly does な particle mean when used with わけ?  
Example (pulled from Google):

> あいつが犯人 **なわけ** がないじゃないか.

I know exactly what this sentence means, but I'm just a little unsure on what
the な is doing there? I couldn't find a suitable answer in my dictionary, the
only thing I can thing of is it being another form of だ.

Thank you in advance.
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2014-05-09T19:54:17.013
15835
2014-05-10T06:19:13.353
2014-05-10T04:52:59.190
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question
grammar particles copula particle-な
わけ accompanied by な particle
You're right, this is a form of だ. You're probably used to seeing な following
_na_ -adjectives. It can be considered the form of だ that appears before
nouns:

> キレイだ ← Here, だ ends a clause.  
>  キレイな花 ← Here, だ changes to な before the noun 花.

But when だ follows a regular noun, it typically doesn't take the な form. The
main exception is when it comes before certain noun-like things including わけ
and の:

> リンゴだ ← Here, だ ends a clause.  
>  リンゴなの ← Here, だ changes to な before the nominalizer の.

The same thing happens in your sentence:

> あいつが犯人だ ← Here, だ ends a clause.  
>  あいつが犯人なわけ ← Here, だ changes to な before the formal noun わけ.

It changes form to な.
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2014-05-10T03:48:39.817
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2014-05-10T06:19:13.353
2014-05-10T06:19:13.353
15835
answer