What is silk card?? Can i use it in an inkjet printer?

Answer 1

It's just a cardstock that's strong and waterproof. It will work in a home printer that can handle #80 thick paper, but you would want laser, not inkjet, because the card stock is slippery and the ink will smudge.
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Answer 2

Very smooth card for commercial printers is called art card and is mostly used for magazines and brochures because it enhances photographs in the same way that photo glossy paper does with inkjet printing.
The finishes are:-
Matt - ultra smooth but not shiny
Velvet - just a hint of shine
Silk - light shine
Gloss - shiny
High Gloss - very shiny

Printers stock is not designed to work in an inkjet printer (except for items such as letterheads). I have had mixed results trying them on an inkjet printer. Some work well but on others the ink soaks into the paper and gives blurry images. Ask for a few sample sheets and try them out using different print settings, you won't harm your printer.