Words that start with 'i' and contain 'rat'

What's the biggest word you can assemble with the combination of letters specified?
The biggest word located by Dictionarypedia is 'interstratification'.

What's the highest scoring word you can play in Scrabble ?
As there are an overwhelming 394 entries, your best option is 'imperata' which scores 12 points overall.

Is there a specific word from this page of word that starts with 'i' and includes 'rat' which could be considered as unusual?
The most unusual word from this list is 'illustratively'. According to the dictionary, 'illustratively' means "By way of illustration or elucidation. [R.] Sir T. Browne.".

Is there a word on this page that stands out as the most popular?
When it comes to well-known words, there's 'inaccurate' which ranks as the 5295^th most popular word.

What is the total number of words you're able to make using words that start with 'i' and include 'rat'?
Overall, you'll find 394 words.