How do i know which chemical reaction will proceed?

Question

How do i know which chemical reaction will proceed?

For instance, which of these will proceed and what will be the products?

(a) Li (s) + H2O (l) -->
(b) K (s)+ H2O (l) -->
(c) Cu (s) + AgNO3 (aq) -->
(d) Fe (s) + Nacl (aq) -->
(e) Mg (s) + Ca(NO3)2 (aq) -->

Answer 1

These are all redox reactions, or at least they would be if they all occurred. The best way to think of it is that one atom in the reaction is giving up electrons to another.



Take the first reaction. When balanced, it should read:



2Li(s) + 2H2O ----> 2LiOH + H2(g)



In the starting materials, Li(s) is in the 0 oxidation state, H is in the +1 oxidation state, and O is in the 2- oxidation state. Here, two lithium atoms will each give up one electron to an H+ atom from water. The two hydrogen atoms formed by this process combine and make H2 gas.



You can predict this because in the table of oxidation potentials in your book, Li is above H (it has a more positive oxidation potential value). This means that 2Li(s) ---> 2Li+ + 2e- happens more forcefully than 2H -----> 2H+ + 2e-, which means that the oxidation of lithium will drive the oxidation of hydrogen backwards. Oxygen cannot accept the electrons because O does not go from 2- to 3- or 4-, ever, because that would give O more than on octet of electrons around it.



So that's how you use the oxidation potential tables to predict which of your reactions proceeds. Each reaction has a set of atoms that can exchange electrons. Reaction B will occur, because K is above H in the oxidation tables. Reaction C will occur, because Cu(0) is higher on the table than Ag is, so Cu will force electrons on Ag+. Reaction D will not occur, because Fe(0) will not force electrons onto either Cl- or to Na+. Reaction E will not occur, because Ca is above Mg on the oxidation potential table, meaning that Mg(s) cannot force Ca2+ to accept electrons.



Reaction E can occur because the N atom (+5) can accept electrons from the Mg. I think there needs to be a source of protons around for that to happen, though, so likely the answer is still "no."



So that's how it's done in a qualitative fashion. If the atom in the reactants that is in the (0) oxidation state is higher on the table than the atom in the (+) oxidation state, then a redox reaction will take place.

Answer 2

The reactions you have shown here are for metals ,which in general follow the activity series,as shown below :



Metals Metal Ion Reactivity

K K+

Na Na+

Li Li+

Ca Ca2+ reacts with water

Ba Ba2+

Sr Sr2+

Mg Mg2+ reacts with acids

Al Al3+

Mn Mn2+

Zn Zn2+

Cr Cr2+

Fe Fe2+

Cd Cd2+

Co Co2+

Ni Ni2+

Sn Sn2+

Pb Pb2+

H2 H+ included for comparison

Sb Sb3+ highly unreactive

Bi Bi3+

Cu Cu2+

Hg Hg2+

Ag Ag+

Au Au3+

Pt Pt+

A metal can replace metals listed below it in the activity series, but not above. For example, sodium is highly active and thus able to replace hydrogen from water:



2 Na (s) + 2 H2O (l) → 2 NaOH (aq) + H2 (g)

Metals that can replace hydrogen within acids but not water are listed in the middle of the activity series, for example zinc replaces hydrogen in sulfuric acid:



Zn (s) + H2SO4 (aq) → ZnSO4 (aq) + H2 (g)

The reactivity series has applications in electrochemistry, where two dissimilar metals are chosen as electrodes of a battery ..



The reactivity series determines qualitatively characteristics such as the reactions with water, air and acids as demonstrated above. However it is defined by the nature of the metals in single displacement reactions.



When a metal in elemental form is placed in a solution of a metal salt it may be, overall, more energetically feasible for this "elemental metal" to exist as an ion and the "ionic metal" to exist as the element. Therefore the elemental metal will 'displace' the ionic metal over time, thus the two swap places. Only a metal higher in the reactivity series will displace another.



From this explaination it can be seen that equation (a),(b), (c) are possible but (d) and (e) are not possible .



(a) 2Li(s) + 2H2O (l) -------->2 LiOH (l) +H2 (g);



(b) 2 K(s) + 2H2O(l) ---------> 2 KOH(l) +H2 (g);



(c) Cu(s) + 2AgNO3(aq) ------> Cu(NO3 )2 +2 Ag(s)

Answer 3

actually u will hav 2 go back 2 your basic theory u hav learnt in ur class

the first reaction will proceed since all alkali metals hav a property that they react with water vigourously

similarly the second reaction will also proceed(k is an alkali metal)

third reaction will proceed since Ag is less reactive than Cu (more reactive metal displaces a less reactive metal)

fourth & fifth reactions will not proceed as Fe is less reactive than Na and Mg is also less reactive than Ca.

i hope u hav understood everything.

Answer 4

Many chemical reactions matter on 2 reactant molecules entering actual touch with one yet another or colliding. The frequency of collision will boost with the temperature simply by fact the well-known molecular velocity will boost. So, simply by fact the molecules are transferring swifter, they collide extra regularly. yet differently to think of why chemical reactions velocity up at larger temperatures is by using the Arrhenius courting describing the temperature dependence of the cost consistent. ok = A*exp(-Ea/RT) in this courting, Ea is the "activation power". simply by fact the temperature will boost, a extra robust fraction of molecules would have adequate power to conquer Ea. Mathematically, that's considered simply by fact at larger T, RT will become great and the exponential area comes nearer to unity (e to a selection that gets nearer and nearer to 0 as T gets great) and the chemical reaction could attain a restricting fee. (even nevertheless, in collision concept, the Arrhenius a element additionally has some temperature dependence.)

Answer 5

According to the reactivity series Li>K>Na>Mg>Al>Zn>Fe>Ni>Sn>Pb>H>Cu>Ag>Au>Pt

a),b),c) will react the remaining two will not work.

Reactivity Series is helpful for displacement reactions.