Question: To talk about something or someone, we usually give an apostrophe, like John's pen. If the word ends with s, we say Adams' pen . But what if we are talking of something that ends with an apostrophe s like Jack's (what we sometimes say in short for Jack's home, or Jack's kitchen etc.). How do I use an apostrophe for words like these? (For eg. If I want to say "Jack's house is closed" but I want to write *Jack's* instead of *Jack's house* , How do I manage the apostrophe?)

Answer: 
*Jack's* is still the correct way of saying the house belongs to Jack, whether or not you use the word *house* after it.

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> "Have you ever been inside the house at 334 Elm Street?"
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> "Oh yeah, that's Jack's house."
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Or,

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> "Which of those three houses is Jack's?"
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> "That's Jack's" (pointing to the Cape Cod with the tan shingles).
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Two different ways of saying the same thing.
The punctuation usage of the possessive apostrophe have evolved according to the whims of the print media.
In the USA : They only use an apostrophe if the word is **2 syllables** or more: Thomas’ report, Rogers’ network. 
For **1 syllable** words they add an apostrophe plus an “s” – Jones’s diary or Chris’s meeting.

In the UK : They add an apostrophe plus **“s”** to make all names possessive: Robert Francis’s book.