On what basis the journals are classified to be National or international. Is it on the basis of Publishing country or some other criteria are applicable?
Yes, the factors listed by Arash Zibaee are crucial. Another important factor is indexing. These parameters give an indication as to the seriousness of the Editorial Board and the quality of articles published. However it should be noted that a journal published in any country can merit classification as 'international' by researchers resident in that country if it meets these criteria. In other words, the classification is not restricted by geographical location of the publishers. By the same argument, journals published outside one's country are not necessarily all international in status. One should also not place too much premium on speed of the review process. Many high brow journals take weeks and even months to review manuscripts (due to thoroughness), while some journals (not so reputable ones) accept manuscripts with minimal delay and little or no review.
I think that the geographic focus is also relevant.
For example, I wrote an article recently that was MAINLY about the relevancy of American privacy law on use of social media for classroom activities. It is a good paper, but was better for a national journal than an international one, because the law is not relevant outside the USA.
I think that JCR (ISI List Tompson roeuter) and The Scimago Journal Rank (SJR) provide social or scientific journals (National or international) may give you good information.
DESCRIPTION OF SCIMAGO JOURNAL RANK INDICATOR
The Scimago Journal Rank (SJR) is based on the transfer of prestige from a journal to another one; such prestige is transferred through the references that a journal do to the rest of the journals and to itself. Open the list and follow online.