硼氢化钠在氢氧化钠溶液中的密度和黏度

摘要

Sodium borohydride with different weights were put into sodium hydroxide solution with mass fraction of 13.35% at 291,298,303 K respectively.Density and viscosity of the mix solutions were determined by pycnometer method and Ubbe-lohde-type glass capillary tube viscosimeter respectively. Then apparent mole volume could be calculated in accordance with the density of the mixed solutions and the influence of concentration changing on the density of mixed solution was discussed. Result showed that the density of the mixed solutions decreased when the concentration of sodium borohydride increased.The viscosity coeffcients (B) of sodium borohydrideand borohydride ion(BH4-) were also calculated according to the viscosity of the mixed solutions and radius of borohydrideion.It was demonstrated that borohydride ion was structure making ion and the coefficient B of the mixed solutions reduced gradually with temperature increasing.%在291、298、303 K下,将不同质量的硼氢化钠固体分别加入到质量分数为13.35％的氢氧化钠溶液中,用密度瓶法和Ubbelohde黏度管分别测量溶液密度和黏度.根据溶液的密度计算硼氢化钠溶液的表观摩尔体积,讨论浓度的变化对混合溶液密度的影响,可知随着硼氢化钠浓度的加大,密度逐渐减小.根据溶液黏度数据和BH-4半径计算了不同温度下硼氢化钠和BH-4的黏度系数B,结果表明,BH-4是结构促进型离子,且随着温度升高,黏度系数B逐渐减小.