Yes it is: since salt is a mineral and not produced from an animal source, it is considered parve - that is, kosher laws do not apply to it and it can be eaten by Jewish people with any parve or kosher food.
I suspect you've seen kosher salt and made the common mistake - one made even by many Jewish people - of assuming that it's actually kosher. You can be easily forgiven for that, because the name suggests this to be the case. However, it's a bit of a misnomer, and a better name would be koshering salt - the name by which it is usually known in Britain. It's so-called because it's used during the process of koshering meat. To be kosher, meat must have all traces of blood removed from it because even the tiniest speck of blood makes food treif - the word which, though literally meaning torn, is used for any non-kosher food - and as such cannot be eaten by Jews. To get rid of the blood, the meat is covered with koshering salt which absorbs all the blood and can then be discarded.
So, to answer your question, you can use any type of salt you like when cooking and - provided you've observed all the other kosher laws - the food will remain kosher.
no
Kosher salt is free of iodine, and additive-free.
Most salt is kosher by default unless additives such as flavourings are added, at that point the salt would have to be certified kosher. 'Kosher salt' refers to a large grain salt that is used during the process of kashering meat. Iodized salt is kosher.
Yes
Yes, you can. Kosher salt is the same as table salt, only a larger granule.
Generally it is not, but check the label to be sure.
Yes.
Iodized salt usually is a form of processed table salt, of which the grains are very fine (about 1/8 of a cubic millimeter each). Kosher salt (iodized or not) is salt that is used for koshering meat. Its grains are considerably larger than those of table salt (though sizes of Kosher salt grains vary).
By default, salt is kosher unless something is added to it to make it not kosher - usually flavourings. Kosher salt may or may not be iodized, you'd have to check the label on the package to be sure.
Iodized salt helps prevent goiter and mental retardation. The non-iodized salt helps maintain the color and texture of pickled food and it does not affect the taste of food when cooking.
Kosher food may be made with kosher salt, but it doesn't have to be. It can be made just as well with sea salt, garlic salt, celery salt, low salt, or no salt, depending on the preferences of the people who are planning on eating it. For that matter, it can also be made with freshly ground black pepper, as well as with cumin, thyme, lemon zest, dry mustard, cinnamon, cardamom, parsley, sage, rosemary, and curry. You name it.
A solution of sodium chloride is called salted water or brine.