Write balanced equations for the following reactions: (d) arsenic trioxide with aqueous potassium hydroxide.

Video transcript

hey everyone in this example, we need to choose the balanced equation that best represents the reaction between phosphorus Penta oxide, P 205 and sodium hydroxide. So we're going to write out our reaction, we have phosphorus Penta oxide. We should recognize that according to this formula, we have phosphorus which is a non metal bonded to another. Non metal being oxygen. And because we have these two non metals bonded in an oxide molecule, we would recall that the greater the metallic character of an oxide will correspond to a greater acidity. And so we can confirm that phosphorus Penta oxide is an acidic oxide. So now we want to write out the formula for sodium hydroxide being N. A. O. H. And we should recall that sodium hydroxide is a base. Now whenever we have specifically the base sodium hydroxide reacting with an acid, this is going to form a neutralization reaction. And we should recall that in neutralization reactions, our products are going to be a salt where we form the salt, N. A., three p. 0. four sodium phosphate. And then our second product for a neutralization reaction we should recall is always going to be water. So this would be our reaction. And now we need to make sure that this is balanced. So we're going to compare our reactant side to our product side. So on a reactive side we have two phosphorus atoms, a total of six oxygen atoms. We have one hydrogen atom and one sodium atom moving onto our product side, we have a total of one phosphorus atom for oxygen, we have a total of five oxygen atoms for hydrogen, we have two hydrogen and for sodium we have three. So we're going to start by balancing out our sodium atoms and we're going to go ahead and place a coefficient of two in front of our sodium phosphate. So now we have six sodium atoms on the product side, which also changes our number of phosphate atoms to a total of two on the product side. And then for oxygen, we're now going to have nine oxygen atoms. Now to compensate for this change on the reactant side, we want to also end up with six sodium atoms. So we're going to place a coefficient of six in front of our sodium hydroxide. So we'll just use a different color here, replace six here in purple. And that's going to change our sodium to now six on the reactive side. So now our sodium are balanced. Looking at our oxygen's on the reactive side, that changes to now 11, oxygen's on our reactant side. And then our hydrogen atoms changed to a total of six hydrogen atoms on our reactant side. So so far we've balanced out our phosphorus atoms and our sodium atoms and now we want to fix our oxygen and hydrogen atoms. So now we're going to go ahead and place a coefficient of three on the product side in front of our water product. And so that's going to change our number of oxygen atoms to now a total of because we have eight here And then plus three Of our oxygen atoms would give us 11. And then that also changes our oxygen two. Now we're sorry, our hydrogen to now a total of six Atoms on the product side, which is now balanced on both the reactant side and product side. So now we have everything fully balanced. And to complete this example, we would say that this written out balanced equation is our final answer here. So everything boxed in is our final answer. I hope that everything I reviewed was clear, but if you have any questions, please leave them down below and I will see everyone in the next practice video.