(1)pH=12 的NaOH溶液中氢氧根离子浓度是0.01mol/L,pH=11的氢氧化钠溶液中氢氧根离子浓度是0.001mol/L,pH=10的氢氧化钠溶液中氢氧根离子浓度是0.0001mol/L,
设加入pH=10的NaOH溶液体积是V2,
c1V1+c2V2=c3(V1+V2)=0.01mol/L×0.1L+0.0001mol/L×V2=0.001mol/L(0.1+V2),
V2=1L=1000mL,
故答案为:1000;
(2)pH=2的HCl溶液中氢离子浓度是0.01mol/L,设加入盐酸的体积是V,
c(OH-)=
=n(碱)?n(酸) V(酸)+V(碱)
=0.001mol/L,0.01mol/L×(0.1?V)L (0.1+V)L
V=81.8mL,
故答案为:81.8;
(3)pH=12 的NaOH溶液中氢氧根离子浓度是0.01mol/L,pH=11的氢氧化钠溶液中氢氧根离子浓度是0.001mol/L,设加入水的体积是V2,c1V1=c2(V1+V2)=0.01mol/L×0.1L=(0.1+V2)L,V2=
=0.9L=900mL,0.01mol/L×0.1L 0.001mol/L
故答案为:900.