Λm°H2O can be represented by-

a.  Λ°m(HCl)+Λ°m(NaOH)°-ΛmNaCl°

b.  Λ°mHNO3+Λ°mNaNO3-ΛmNaOH°

c.  Λ°mHNO3+Λ°mNaOH-ΛmNaNO3°

d.  Λ°mNH4OH+Λ°m(HCl)-Λ°mNH4Cl


1. (a, b)
2. (b, c)
3. (c, d)
4. (a, c)

(a)
Λ°m(HCl)=Λ°mH++Λ°mCl-
Λ°m(NaOH)=Λ°mNa++Λ°mOH-
Λ°m(NaCl)=Λ°mNa++Λ°mCl-
               -           - 
Λ°mHCl+Λ°m(NaOH)-Λ°m(NaCl) =Λ°mH++Λ°mHO-
(d) 
Λ°mNH4OH=ΛmNH4+°+Λ°mOH-
Λ°m(HCl)=Λ°mH++Λ°mCl-
Λ°mNH4Cl=Λ°mNH4+ +Λ°mCl-
-              -            -
Λ°mNH4OH+Λ°m(HCl)-Λ°mNH4Cl
         =ΛmH+°+ΛmOH-°=ΛmH2O0
This type of decomposition is not possible due to weak basic strength of NH4OH. This line will be placed above.
(b) 
Λ°mHNO3=Λ°mH++Λ°mNO3-
Λ°mNaNO3=ΛmNa+0+ΛmNO3-0
Λ°m(NaOH)=ΛmNa+°+Λ°mOH-
  -           -           -
Λ°mHNO3+Λ°mNaNO3-ΛmNaOH°
       =ΛmH+°+2ΛmNO3--ΛmOH-°
(b) is incorrect
(c) 
Λ°mHNO3=Λ°mH++Λ°mNO3-
Λ°m(NaOH)=ΛmNa+°+Λ°mOH-
Λ°mNaNO3=ΛmNa+0+ΛmNO3-0
  -           -           -
Λ°mHNO3+ΛmNaOH°-Λ°mNaNO3
       =ΛmH+°+2ΛmOH--ΛmH2O°
Hence, Options (a) and (c) are the correct choices.