It is desirable that pesticides eventually decompose in the environment to give harmless products. If the half-life for the decomposition of a certain pesticide is 10.2 years, and

the present concentration of this pesticide in a lake is 3.1 × 10-5 /mL, what was its

concentration 4 years ago?​

Benzonitrile (c6h5cn) is reduced to two different products depending on the reducing agent used. treatment with lithium aluminum hydride followed by water forms k, which has a molecular ion in its mass spectrum at 107 and the following ir absorptions: 3373, 3290, 3062, 2920, and 1600 cm-1. treatment with a milder reducing agent forms l, which has a molecular ion in its mass spectrum at 106 and the following ir absorptions: 3086, 2850, 2820, 2736, 1703, and 1600 cm-1. l shows fragments in its mass spectrum at m/z = 105 and 77. propose structures for k and l and choose an explanation for how this could be concluded.