I am using an op amps (LM 358) in my circuit which has more amplifiers then I need.
Can I leave unused amplifier as terminals not connected anywhere?

 

Nope. You have to tame those puppies so they don't wander around and oscillate due to stray capacitance and leakage currents. Pick a stable voltage for the non-inverting input, connect the output to the inverting input and tell them to sit, stay.

 

See this link
https://e2e.ti.com/blogs_/archives/b/thesignal/archive/2012/11/27/the-unused-op-amp-what-to-do