Question: how to solve system with exponential equation

Hello,

I want to ask, I have a system of equations... 

eq1:=K_1=(((n_Cl-x)*u_Cl)*(n_H*u_H))/(n_HCl*m);
eq2:=K_2=(((n_Na-x)*u_Na)*(n_OH*u_OH))/(n_NaOH*m);
eq3:=K_w=(n_H*u_H/m)*(n_OH*u_OH/m);
eq4:=K_NaCl=((n_Na-x)*u_Na*(n_Cl-x)*u_Cl)/m^2;
eq5:=(n_NaCl-x)=(n_Na-x)+n_NaOH;
eq6:=(n_NaCl-x)=(n_Cl-x)+n_HCl;
eq7:=(n_Na-x)+n_H=(n_Cl-x)+n_OH;
eq8:=2*ionic=(n_H/m)+((n_Cl-x)/m)+((n_Na-x)/m)+(n_OH/m);
eq9:=u_H=0.4077*ionic^2-0.3152*ionic+0.9213;
eq10:=u_Na=0.0615*ionic^2-0.2196*ionic+0.8627;
eq11:=u_OH=0.1948*ionic^2-0.1803*ionic+0.8887;
eq12:=m=r*V;
eq13:=u_Cl=(1.417625986641341e-01)*exp^(-ionic/2.199955601666953e-02)+2.369460669647978e-01*exp^(-ionic/3.756472377688394e-01)+5.859738096037875e-01;

but when I use solve command, Maple starts computing, but suddenly gives message: Solutions may have been lost. 

I guess problem is the last exponential equation. Is there any way how to make Maple to be able to compute this system?