Propose structures for compounds that fit the following descriptions:

(a) C₁₀H₁₄

H NMR: 7.18 δ (4 H, broad singlet); 2.70 δ (4 H, quartet, J = 7 Hz); 1.20 δ (6 H, triplet, J = 7 Hz)

IR: 745 cm ^–1

(b) C₁₀H₁₄

H NMR: 7.0 δ (4 H, broad singlet); 2.85 δ (1 H, septet, J = 8 Hz); 2.28 δ (3 H, singlet); 1.20 δ (6 H, doublet, J = 8 Hz)

IR: 825 cm ^–1