（11分）过氧化氢是重要的氧化剂和还原剂，常用于消毒、杀菌、漂白等。某化学兴趣小组同学围绕着过氧化氢开展了调查研究与实验。

Ⅰ．调查

（1）通过查阅资料，发现过氧化氢的沸点为152.1℃，而相对分子质量相同的硫化氢的沸点为－60.4℃，造成两者沸点差异大的主要原因是                     ；

（2） 资料显示，过氧化氢制备目前最常用的是乙基蒽醌法，其主要过程可以用如图所示，写出此过程的总反应方程式是                                  。

Ⅱ．不稳定性实验研究

（3）为了探究温度、催化剂等外界条件对H₂O₂的分解速率的影响，某兴趣小组同学设计了如下三组实验，部分实验数据已经填在下面表中。

②三组实验中分解速率最快的是               （填编号）。

Ⅲ．过氧化氢含量的实验测定

兴趣小组同学用0.1000 mol·L^-1酸性高锰酸钾标准溶液滴定试样中过氧化氢的含量，反应原理为：2MnO₄^－＋5H₂O₂＋6H^＋ =2Mn^2＋＋8H₂O＋ 5O₂

（4）滴定到达终点的现象是__________________________________________________。

（5）用移液管吸取25.00mL试样置于锥形瓶中，重复滴定四次，每次消耗的 KMnO₄标准溶液体积如下表所示：

（6）若滴定前尖嘴中有气泡，滴定后消失，则测定结果      (“偏高”或“偏低”或“不变”)。

True, some of the attacks against whites by blacks are for money and valuables. But, others ale revenge assaults by blacks for a real or imagined racial insult. It is equally true that the vast majority of violent crimes against whites are committed by whites, while the vast majority of violent crimes against blacks are committed by other blacks. Yet even after discounting crimes that are hastily and erroneously (错误地，不正确地) tagged as racially motivated, many blacks do attack whites because they all white. A 1998 Justice Department study confirmed that nearly 20% of the more than 4,000 hate crimes well committed against whites, and their attackers were blacks. The Southern Poverty Law Center also notes that there is a huge escalation in black-on- white violence from nearly none at the beginning of the 1990s.
A collection of white supermacists and rightist extremist groups have eagerly made black-on- white violence a wedge issue in their movement to paint blacks as the prime racial hate mongers in America. The New Century Foundation, an ultra-conservative think-tank, has launched a full- blown national campaign to alert whites to the danger of black hate crimes. These groups and individuals magnify hate crimes by blacks in order to back their social agenda. They oppose affirmative action programs and per hate crime laws. They downplay, or justify, the proliferation of white-supremacist-tinged paramilitary groups, police violence, and racial profiling. And they lobby hard for more prisons, police, and tougher laws.
Black-on-white violence also reinforces white fears of blacks as the ultimate menace to society. When blacks say or do nothing about these attacks, it is taken by some as a tacit signal that blacks put less value on white lives than black lives. This is a terrible price for black silence on hate crimes committed by blacks.

What can be inferred according to this passage

A. Some crimes are racially motivated.
B. All black people hate white people.
C. There’s racial discrimination only in America.
D. America is not a good place for immigrants for its serious black-on-white violence.