Có dung dịch riêng rẽ các chất sau: CH3COOH, CH2=CHCOOH, CH3CHO, CH3CH2OH. Để phân biệt các dung dịch trên cần dùng ít nhất các thuốc thử nào sau đây?
Có dung dịch riêng rẽ các chất sau: CH3COOH, CH2=CHCOOH, CH3CHO, CH3CH2OH. Để phân biệt các dung dịch trên cần dùng ít nhất các thuốc thử nào sau đây?
A. Quỳ tím, dung dịch AgNO3/NH3 và nước bromine.
B. Quỳ tím và nước bromine.
C. Dung dịch AgNO3/NH3 và nước bromine.
Hãy suy nghĩ và trả lời câu hỏi trước khi xem đáp án
- Bước 1: Dùng quỳ tím.
- $CH_3COOH$ và $CH_2=CHCOOH$ làm quỳ tím hóa đỏ.
- $CH_3CHO$ và $CH_3CH_2OH$ không làm đổi màu quỳ tím.
- Bước 2: Phân biệt $CH_3COOH$ và $CH_2=CHCOOH$, ta dùng nước brom: $CH_2=CHCOOH$ làm mất màu nước brom. $CH_2=CHCOOH + Br_2 \rightarrow CH_2Br-CHBr-COOH$
- Bước 3: Phân biệt $CH_3CHO$ và $CH_3CH_2OH$, ta dùng dung dịch $AgNO_3/NH_3$: $CH_3CHO$ tạo kết tủa Ag. $CH_3CHO + 2AgNO_3 + 3NH_3 + H_2O \rightarrow CH_3COONH_4 + 2Ag + 2NH_4NO_3$
Câu hỏi liên quan
Một con lắc lò xo dao động không ma sát trên mặt phẳng nằm ngang thì
Trong không gian \[Oxyz\] (đơn vị trên mỗi trục tọa độ là mét), một ngôi nhà như hình vẽ dưới đây có sàn nhà nằm ngang trên mặt phẳng \[\left( \alpha \right):2x + y - 3z + 18 = 0\]. Hai mái nhà lần lượt nằm trên các mặt phẳng \[\left( P \right):x - y = 0\], \[\left( Q \right):x + y - 2z = 0\]. Hỏi chiều cao của ngôi nhà tính từ sàn nhà đến nóc nhà (điểm cao nhất của mái nhà) là bao nhiêu mét (làm tròn kết quả đến hàng phần chục)?
Vi khuẩn sinh sản chủ yếu bằng hình thức nào sau đây?
Hệ thống những quy tắc xử sự mang tính bắt buộc chung do Nhà nước ban hành và được bảo đảm thực hiện bằng quyền lực nhà nước là nội dung của khái niệm nào sau đây?
- Các electron của nguyên tử nguyên tố X được phân bố trên 3 lớp, lớp thứ ba có 6 electron. Số đơn vị điện tích hạt nhân của nguyên tử nguyên tố X là bao nhiêu?
Đối với những hành vi vi phạm đạo đức trong kinh doanh, chúng ta cần làm gì?
Read the following passage about the The Importance of Social Media in Modern Society and mark the letter A, B, C or D on your answer sheet to indicate the best answer to each of the following questions from 31 to 40.
In the 21st century, social media has become a crucial element of everyday life[I]. Platforms such as Facebook, Twitter, Instagram, and TikTok link individuals around the world, [IV]. Although some may critique social media for promoting negativity, it is important to acknowledge its numerous positive effects on society[III]. This essay will delve into the importance of social media, its influence on shaping public perception, and the challenges it poses.[II]
One of the primary benefits of social media is its ability to foster communication and connection. People can maintain relationships with friends and family, regardless of geographical barriers. This aspect is particularly vital for those who live far away from loved ones. For example, a student studying abroad can easily share their experiences with family through posts, photos, and video calls. Furthermore, social media enables individuals to connect with like-minded people and build communities around shared interests or causes. Activist groups, for instance, often use social media platforms to rally support for important issues, raising awareness and mobilizing action more efficiently than traditional methods.
Moreover, social media serves as a powerful tool for information dissemination. News spreads rapidly through these platforms, allowing individuals to stay informed about current events. During emergencies, such as natural disasters, social media can provide crucial information in real time, helping people stay safe and informed. However, this rapid dissemination of information also raises concerns about the accuracy and reliability of the content being shared. Misinformation can spread just as quickly as legitimate news, leading to confusion and mistrust.
Despite the challenges posed by misinformation, social media plays a significant role in shaping public opinion. People often turn to these platforms to voice their opinions and engage in discussions on various topics. For instance, political debates and social movements frequently gain traction through social media, allowing individuals to express their views and influence others. This democratization of discourse can empower marginalized voices and facilitate social change. However, it is crucial to approach online discussions critically, as echo chambers can form, reinforcing existing beliefs rather than encouraging open dialogue.
In conclusion, while social media presents challenges such as misinformation and polarized discussions, its positive contributions to communication, information dissemination, and social activism cannot be overlooked. As society continues to evolve, it is essential to harness the potential of social media while being mindful of its pitfalls. By promoting responsible use and critical thinking, we can maximize the benefits of social media and foster a more connected and informed society.
According to the paragraph 2, which of the following is NOT a benefits of social media?
Read the following passage about gender equality and mark the letter A, B, C, or D on your answer sheet to indicate the best answer to each of the following questions from 31 to 40.
GENDER EQUALITY TODAY
Gender equality is a fundamental human right and a critical foundation for a peaceful, prosperous, and sustainable world. [I] Despite significant progress in recent years, gender inequality remains a pressing issue across the globe. [II] Women continue to be underrepresented in leadership positions and face numerous barriers in various sectors, including education, healthcare, and the workforce. [III] According to the World Economic Forum’s Global Gender Gap Report 2021, it will take an estimated 135.6 years to close the gender gap globally if current trends continue. [IV]
In many countries, women are still subjected to discrimination and violence. Gender-based violence, including domestic violence and sexual harassment, affects millions of women worldwide and hinders their ability to participate fully in society. Additionally, cultural and societal norms often perpetuate stereotypes that limit women’s roles and opportunities.
However, there are positive signs of change. Movements advocating for gender equality have gained momentum, and more individuals are recognizing the importance of women’s rights. Governments and organizations are implementing policies to promote equal opportunities and protect against discrimination. Education plays a vital role in this transformation, as empowering girls through education can lead to improved economic outcomes and healthier communities.
Achieving gender equality is not only a matter of fairness; it is essential for the advancement of society as a whole. By ensuring equal rights and opportunities for all genders, we can create a more just and equitable world.
(Adapted from United Nations. “Gender Equality.” UN Women. 2021)
According to paragraph 2, which of the following is NOT a reason preventing women from fully participating in society?
Read the following passage about news and mark the letter A, B, C or D on your answer sheet to indicate the best answer to each of the following questions from 31 to 40.
[I] Wildlife conservation refers to the efforts made to protect and preserve wild animal species and their habitats. [II] It is crucial for maintaining biodiversity, which plays a vital role in ecosystem stability and health (Smith & Jones, 2018). [III] Unfortunately, many species are threatened due to habitat destruction, poaching, and climate change, making conservation efforts more urgent than ever. [IV]
One of the primary reasons for wildlife conservation is the preservation of biodiversity. A diverse range of species contributes to ecosystem services, such as pollination, water purification, and climate regulation. The loss of a single species can disrupt these services and lead to ecological imbalances. For instance, the decline of pollinators like bees has serious implications for food production and agriculture (Global Biodiversity Outlook, 2020).
Moreover, wildlife conservation has significant economic benefits. Many communities depend on ecotourism, which relies on healthy wildlife populations and intact ecosystems. According to a study by the World Wildlife Fund (WWF), ecotourism can generate billions of dollars in revenue, providing jobs and supporting local economies (WWF, 2021). Protecting wildlife not only safeguards natural resources but also creates sustainable livelihoods for local populations.
However, effective wildlife conservation requires a collaborative approach. Governments, non-governmental organizations, and local communities must work together to implement policies and strategies that promote conservation efforts. Community-based conservation initiatives, where local people actively participate in protecting their natural resources, have shown promising results. These initiatives empower communities and ensure that conservation efforts are tailored to local needs and contexts (Bennett & Dearden, 2014).
According to paragraph 2, which of the following is NOT a reason for wildlife conservation?
Read the following advertisement and mark the letter A, B, C, or D to indicate the option that best fits each of the numbered blanks from 1 to 6.
EXPERIENCE THE FUTURE AT THE ROBOT EXHIBITION!
Get ready to immerse (1) ______ the fascinating world of robotics! This extraordinary exhibition, (2) ______, stunning designs, and interactive displays, is perfect for all ages. Explore various robots, (3) ______ amazing capabilities, from performing delicate tasks to engaging in lively conversations. Busy (4) ______ the innovations shaping our future, you’ll be captivated by the endless possibilities of automation. Don’t miss your chance to (5) ______ a ticket to the exhibition and witness the latest advancements in robotics firsthand. Join us for an (6) ______ experience that will inspire and educate. Get your tickets today and step into tomorrow!
Busy (4) ______ the innovations shaping our future, you’ll be captivated by the endless possibilities of automation.Loại máy móc nào sau đây có thể thay thế trâu trong canh tác
Virus bám vào tế bào chủ nhờ các gai glycoprotein hoặc protein bề mặt của virus tương tác đặc hiệu với các thụ thể trên bề mặt của tế bào chủ là đặc điểm của giai đoạn nào?
Một loài động vật ngẫu phối, con đực có cặp NST giới tính XX, con cái có bộ NST giới tính XY. Xét 3 gene, trong đó: gene thứ nhất có 4 allele nằm trên NST giới tính X, không có allele tương ứng trên Y; gene thứ hai và thứ ba đều có 3 allele nằm trên vùng tương đồng của NST giới tính X và Y. Số loại kiểu gene tối đa về các gene trên là bao nhiêu?
Nơi nào diễn ra sự hô hấp mạnh nhất ở thực vật?
Làm thế nào để di chuyển cả ảnh và khung ảnh (canvas)?
Paladium(II) có xu hướng tạo thành các phức có số phối trí 4. Một hợp chất có công thức Biết rằng phối tử rất khó tham gia phản ứng trao đổi ion. Khi xử lý 1 mol với một lượng dư (aq) trong nước thì có bao nhiêu mol AgCl(s) được tạo thành?
Mệnh đề nào sau đây là sai khi nói về việc kết nối thiết bị thông minh vào mạng máy tính?
Một vật được kéo đều trên sàn bằng lực F=20N hợp với phương ngang một góc α. Khi vật di chuyển 1 m trên sàn, lực đó thực hiện được công là \(10\sqrt 3 \)J. Góc α là:
Read the following advertisement and mark the letter A, B, C or D on your answer sheet to indicate the option that best fits each of the numbered blanks from 1 to 6.
Living Every Moment Fully: Secrets to Happiness in the Digital Era
Are you seeking balance in your life? The (1)_________ balance between online and offline worlds awaits you!
Our modern (2)_________ create unnecessary daily life stress in our increasingly connected world. Stolen moments (3)_________ your phone during important conversations add up to lost time. We should remind people (4)_________ the value of being present together.
The secret (5)_________ in finding your perfect digital-life harmony through mindful technology use. Start prioritizing real connections today (6)_________ your life into something meaningful.
Contact us now at Digital Wellness Center for your free consultation!
Pha sáng của quá trình quang hợp diễn ra ở đâu?
