Predict the type of substitution mechanism predict which reaction of the pair will occur at a faster rate

If a || b and e || f, what is the value of y ?

In 1901, thomas edison invented the nickel-iron battery. the following reaction takes place in the battery. fe(s) + 2 nio(oh)(s) + 2 h2o(l) fe(oh)2(s) + 2 ni(oh)2(aq) how many mole of fe(oh)2, is produced when 5.35 mol fe and 7.65 mol nio(oh) react?

What happens when light is scattered?