## 4 Conclusions  
In this work, the experimental viscosity of ethanol-based binary liquid mixtures (Ethanol + 1-hexanol and Ethanol + 1-octanol at 303.15 K) was compared with a value predicted using various theoretical models. With regard to Ethanol + 1-hexanol binary liquid system, it was found that the average percentage of deviation (APD) of viscosity is more in the [PERSON] and [PERSON] model and less in the Kendall and Monroe model. It was therefore concluded that the [PERSON] and [PERSON] model is the most suitable theoretical method for estimating viscosity for the Ethanol + 1-hexanol binary liquid system. Regarding the results derived for the Ethanol + 1-octanol binary liquid system, it was observed that the APD of \(\mathrm{\eta}\) is more in the Hind model and Bingham model and less in the Gambrill model. From the results, it was concluded that the Gambrill model is the most suitable theoretical method for estimating the viscosity of the Ethanol + 1-octanol binary liquid system. Upon \begin{table}
\begin{tabular}{c c c c c} \hline \hline \begin{tabular}{c} **Mole Fraction** \\ **of Ethanol** \\ \end{tabular} & \begin{tabular}{c} \(\mathrm{\beta^{E}}\) \\ **(\(\times\)10\({}^{-10}\) m\({}^{2}\)N\({}^{-1}\))** \\ \end{tabular} & \begin{tabular}{c} \(\mathrm{\lambda^{E}}\) \\ **(\(\times\)10\({}^{-11}\) m)** \\ \end{tabular} & \
\begin{tabular}{c} \(\mathrm{\tau^{E}}\) \(\times\)10\({}^{8}\) Pa \\ \end{tabular} &
\begin{tabular}{c} \(\mathrm{\tau^{E}}\) \(\times\)10\({}^{-12}\) s \\ \end{tabular} \\ \hline \multicolumn{5}{c}{Ethanol + 1-Hexanol} \\ \hline
0.00 & 0.000 & 0.000 & 0.000 & 0.000 \\ \hline
0.14 & \(-\)0.191 & \(-\)0.063 & \(-\)0.157 & \(-\)0.096 \\ \hline
0.28 & \(-\)0.340 & \(-\)0.112 & \(-\)0.288 & \(-\)0.158 \\ \hline
0.49 & \(-\)0.636 & \(-\)0.213 & \(-\)0.458 & \(-\)0.248 \\ \hline
0.64 & \(-\)0.590 & \(-\)0.193 & \(-\)0.463 & \(-\)0.205 \\ \hline
0.77 & \(-\)0.513 & \(-\)0.166 & \(-\)0.381 & \(-\)0.148 \\ \hline
0.87 & \(-\)0.459 & \(-\)0.149 & \(-\)0.298 & \(-\)0.110 \\ \hline
0.95 & \(-\)0.115 & \(-\)0.036 & \(-\)0.148 & \(-\)0.044 \\ \hline
1.00 & 0.000 & 0.000 & 0.000 & 0.000 \\ \hline \multicolumn{5}{c}{Ethanol + 1-Octanol} \\ \hline
0.00 & 0.000 & 0.000 & 0.000 & 0.000 \\ \hline
0.13 & \(-\)0.262 & \(-\)0.090 & \(-\)0.198 & \(-\)0.245 \\ \hline
0.24 & \(-\)0.490 & \(-\)0.168 & \(-\)0.396 & \(-\)0.465 \\ \hline
0.33 & \(-\)0.651 & \(-\)0.223 & \(-\)0.516 & \(-\)0.561 \\ \hline
0.55 & \(-\)0.840 & \(-\)0.282 & \(-\)0.505 & \(-\)0.435 \\ \hline
0.70 & \(-\)0.908 & \(-\)0.302 & \(-\)0.555 & \(-\)0.400 \\ \hline
0.81 & \(-\)0.623 & \(-\)0.201 & \(-\)0.452 & \(-\)0.259 \\ \hline
0.89 & \(-\)0.322 & \(-\)0.100 & \(-\)0.299 & \(-\)0.139 \\ \hline
0.96 & \(-\)0.135 & \(-\)0.041 & \(-\)0.193 & \(-\)0.076 \\ \hline
1.00 & 0.000 & 0.000 & 0.000 & 0.000 \\ \hline \hline \end{tabular}
\end{table} 
Table 9: Excess parameters of binary liquid systems of Ethanol + 1-Hexanol and Ethanol + 1-Octanol at 303.15K [27]. comparing the experimental density of the binary liquid mixtures (Ethanol + 1-hexanol and Ethanol + 1-octanol at 303.15 K) by applying various theoretical models, it was inferred that the APD of the density predicted by the Mchaeweh-Nasrifar-Mashfeghian model is larger and is the least in the [PERSON] model. It was concluded that the [PERSON] et al. model is the most suited to predict the density closest to the experimental results for both the binary liquid systems. On comparing the experimental ultrasonic velocity through values derived through various theoretical models of binary liquid mixtures (Ethanol + 1-hexanol and Ethanol + 1-octanol) at 303.15 K, it was concluded that the APD of the ultrasonic velocity for the Ethanol + 1-hexanol binary liquid system is the most in [PERSON]'s specific velocity relation and the least in [PERSON]'s relation, indicating the best suitability of [PERSON]'s relation for estimating the ultrasonic velocity.