Questions

NOKIA belongs to the countyry Finland.

NH3, Ammonia is a neutral compound as the individual oxidation numbers elements that make up the compound NH3 are Nitrogen (N) and Hydrogen (H) sum to zero. 

We do not speak of the oxidation number of a molecule. We can speak of the oxidation numbers of the individual elements that make up the compound.

Here the oxidation number of Nirogen is -3 and that of Hydrogen is +1.

Now, NH3 = 1(-3) + 3(+1) = -3 + 3 = 0.

The Gulf of Mexico is the largest among all the gulfs in the world.

A gulf is nothing but a large inlet from the ocean into the landmass, typically with a narrower opening than a bay.

The Gulf of Mexico is an ocean basin mostly surrounded by the North American continent. It is a unique, semi-enclosed sea located between the Yucatan and Florida peninsulas, at the southeast shores of the United States.