ACID NaOH; \[{{N}_{1}}{{V}_{1}}={{N}_{2}}{{V}_{2}}\] \[\FRAC{W}{E}\times 1000=\frac{1}{10}\times 25\]; \[\frac{0.16}{E}\times 1000=\frac{25}{10}\] \[M=2\times E=2\times 64=128\].