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Current time:0:00Total duration:6:16

Video transcript

let's continue to rank metals from the most reactive to the least reactive metals for this in this video we are going to react metals with dilute acid and depending on how vigorously they react we will rank them in this particular series in general when metals react with dilute acid we get hargeon gas and with this metal salt is being formed for example if I take sink metal and reacted with dilute HCl so over here zinc will displace the hydrogen so we will get hydrogen gas and it will form zinc chloride plus Zn CL 2 let me just balance this equation here yes along with this we will also have some heat being generated this is an exothermic reaction now let me show you an experiment of the same thing here I have got dilute HCl in the test tube and I'm going to add zinc metal to it you can notice that the moment I add zinc there are some bubbles evolving now that's happening because hydrogen is trying to escape out of the solution and that's why it is forming bubbles and also with this there is heat being generated I can notice that the test tube is getting warmer because of the heat so when a metal reacts with dilute acid we see the bubbling of hydrogen gas and the warming of the test tube now based on these two observations I can tell whether a metal is more reactive or less reactive see if we observe that more amount of hydrogen gas is bubbling out or more heat is being generated then definitely the metal reacting is going to be more reactive whereas if the amount of hydrogen gas coming out is less and the heat being generated is also less in that case the metal is less reactive so let us carry out this experiment with different metals this time we are going to react magnesium with dilute HCl so the products are going to be almost the same in this case also magnesium will displace hydrogen to give off hydrogen gas and will form magnesium chloride which is the metal salt and along with this a lot of heat will be given off so the products will be dis so let's look at this reaction in an actual experiment so here I'm going to add magnesium strips to dilute HCl solution so here you can notice the amount of bubbling this time is much more than what we saw in the case of zinc see you can compare and I can also tell you the heat being generated is much more I can feel the test tube is much warmer in the case of magnesium than in zinc so based on these observations we can say that magnesium is more reactive than zinc let's write it down so magnesium is more reactive than zinc now we can carry out similar experiments for different metals like aluminium iron and copper and rank all of them in a particular series so if you do that you will notice that the maximum bubbling happens in case of magnesium then in case of aluminium then comes zinc and then comes iron the least bubbling happens in case of iron and if you do the same experiment with copper you would not even notice any bubbling at all copper does not even react with the dilute HCl so we can put copper towards the end now with this new information let's update our old ranking of metals you would recall that in previous videos we were reacting metals with water and oxygen and depending on how we're gonna see each reacted we rank them something like this but see there was a problem with this ranking list it wasn't very detailed like over sure you can see that aluminium iron and zinc they all are clubbed together at one rank whereas over here copper and lead they are also clubbed together at one rank we don't know for sure which one is more reactive between them so let's update this with our new information which is aluminum is more reactive than zinc that more reactive than iron so if we do that this is what we will get yes now this list looks much detailed but still there are some problems like copper and lead which is more reactive and for this we will have to carry out more reactions which we will do in later videos but this will suffice for now before we close this video let me give you some details first being that do not react sodium and potassium with acid see these metal are very reactive they even react with cold water right so if you react them with acid the reaction could be very violent very explosive even that's why do not do this now second being that I told you when metals reacted with acid they give off hydrogen gas but that's not true for nitric acid when metals react with nitric acid we do not get a hydrogen gas and that's because nitric acid is a very good oxidizing agent it can add oxygen very easily so here in this case nitric acid oxidizes the hydrogen being produced ad so adds oxygen to it and finally we get water instead of hydrogen only magnesium and manganese are the two metals that can react with a very dilute form of hno3 to give hydrogen gas now let's summarize the video in this video we saw when metals react with dilute acid what gas gets released and based on this we experimented with few metals and we arrange them in the order of their reactivity I hope you are able to recall these blanks and if not then go back and watch the video again