The alkene that exhibits geometrical isomerism is :

The IUPAC name of neopentane is

Arrange the carbanions, $${(C{H_3})_3}\overline C $$, $$\overline C C{l_3}$$ , $${(C{H_3})_2}\overline C H$$, $${C_6}{H_5}\overline C H{}_2$$ in order of their decreasing stability :

Solid Ba(NO₃)₂ is gradually dissolved in a 1.0 $$\times$$ 10^-4 M Na₂CO₃ solution. At what concentration of Ba²⁺ will a precipitate begin to form ?
(K_sp for BaCO₃ = 5.1 $$\times$$ 10⁻⁹ )