Step 1: Reaction Mechanism Analysis
The reaction involves sodium ethoxide (CH$_3$CH$_2$ONa) and tert-butyl chloride [(CH$_3$)$_3$CCl] in ethanol. Due to steric hindrance, tertiary alkyl halides favor elimination (E2) over substitution.
Step 2: Major Product Determination
Sodium ethoxide, a strong base, promotes elimination via the E2 mechanism, yielding an alkene. The resultant product is isobutene (\( CH_2 = C(CH_3)_2 \)). Therefore, the correct option is (B).
A particle is moving in a straight line. The variation of position $ x $ as a function of time $ t $ is given as:
$ x = t^3 - 6t^2 + 20t + 15 $.
The velocity of the body when its acceleration becomes zero is: