If I merge two accounts, what is outcome of posting privileges? One account does not have question asking permission, the other does.
What should be expected if I merge?
Well, first off: if we catch you running multiple accounts to work around posting restrictions (of any sort - suspensions, rate-limits, quality-bans), you'll end up suspended and unable to post or edit anything. Generally, this happens becomes someone complains (re-posting the same poorly-written question on several different accounts is kind of a dead giveaway), but there are all sorts of stupid things that happen to bring this up. See: How should sockpuppets be handled on Stack Exchange?
If you request the merge yourself, the results depend on the state of both accounts - it's effectively the same as if you had just used one account from the start, with rate-limits, quality-checks and suspensions in effect based on the combined histories of both.